Merge pull request 'dev→main: gallery similarity search (Phase 3) + UI/mobile polish' (#63) from dev into main

alembic/versions/0036_siglip_embedding_hnsw_index.py

@@ -0,0 +1,41 @@
+"""image_record.siglip_embedding: HNSW cosine index for "more like this"
+
+Revision ID: 0036
+Revises: 0035
+Create Date: 2026-06-04
+
+Gallery Phase 3 (visual similarity search) ranks images by
+`siglip_embedding.cosine_distance(source_embedding)`. Without an index that's
+a sequential scan computing a 1152-dim distance for every row — fine at small
+scale, but it grows linearly with the library. Add an HNSW index with
+`vector_cosine_ops` so the top-N nearest search is sub-50ms ANN.
+
+1152 dims is under pgvector's 2000-dim HNSW limit, so HNSW (no training,
+better recall than IVFFlat) is the right choice. ONE-TIME COST: building the
+index over the existing embeddings (~57k vectors on the operator's library)
+locks image_record for ~30-60s during this migration on deploy — acceptable
+for a single-operator homelab. NULL embeddings (videos / not-yet-embedded
+rows) are simply not indexed.
+"""
+from typing import Sequence, Union
+
+from alembic import op
+
+revision: str = "0036"
+down_revision: Union[str, None] = "0035"
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    # Raw SQL: alembic's create_index doesn't express the `USING hnsw (...
+    # vector_cosine_ops)` access-method + opclass cleanly. Must match the
+    # query's cosine_distance operator class to be usable by the planner.
+    op.execute(
+        "CREATE INDEX ix_image_record_siglip_hnsw "
+        "ON image_record USING hnsw (siglip_embedding vector_cosine_ops)"
+    )
+
+
+def downgrade() -> None:
+    op.drop_index("ix_image_record_siglip_hnsw", table_name="image_record")

backend/app/api/gallery.py

@@ -10,6 +10,21 @@ from ..services.gallery_service import GalleryService
 gallery_bp = Blueprint("gallery", __name__, url_prefix="/api/gallery")
 
 
+def _image_json(i):
+    """Serialize a GalleryImage for the scroll/similar list responses."""
+    return {
+        "id": i.id,
+        "sha256": i.sha256,
+        "mime": i.mime,
+        "width": i.width,
+        "height": i.height,
+        "created_at": i.created_at.isoformat(),
+        "posted_at": i.posted_at.isoformat() if i.posted_at else None,
+        "thumbnail_url": i.thumbnail_url,
+        "artist": i.artist,
+    }
+
+
 def _parse_date(raw):
     """Parse a YYYY-MM-DD query value to a UTC midnight datetime, or None.
     Raises ValueError (→ 400) on a malformed value."""
@@ -76,20 +91,7 @@ async def scroll():
 
     return jsonify(
         {
-            "images": [
-                {
-                    "id": i.id,
-                    "sha256": i.sha256,
-                    "mime": i.mime,
-                    "width": i.width,
-                    "height": i.height,
-                    "created_at": i.created_at.isoformat(),
-                    "posted_at": i.posted_at.isoformat() if i.posted_at else None,
-                    "thumbnail_url": i.thumbnail_url,
-                    "artist": i.artist,
-                }
-                for i in page.images
-            ],
+            "images": [_image_json(i) for i in page.images],
             "next_cursor": page.next_cursor,
             "date_groups": [
                 {"year": y, "month": m, "image_ids": ids} for y, m, ids in page.date_groups
@@ -98,6 +100,36 @@ async def scroll():
     )
 
 
+@gallery_bp.route("/similar", methods=["GET"])
+async def similar():
+    """Visual "more like this": images ranked by cosine distance to the
+    `similar_to` image's embedding. Composes with the scope filters (AND) but
+    ignores post_id and sort. Bounded top-N, no cursor."""
+    try:
+        similar_to = int(request.args["similar_to"])
+        limit = int(request.args.get("limit", "100"))
+        filters, _sort = _parse_filters()
+    except (KeyError, ValueError):
+        return jsonify({"error": "similar_to query param required"}), 400
+    # post_id is the exclusive post-detail view — not a similarity scope.
+    scope = {k: v for k, v in filters.items() if k != "post_id"}
+    async with get_session() as session:
+        svc = GalleryService(session)
+        try:
+            images = await svc.similar(image_id=similar_to, limit=limit, **scope)
+        except ValueError as exc:
+            return jsonify({"error": str(exc)}), 400
+    if images is None:
+        return jsonify({"error": "not found"}), 404
+    return jsonify(
+        {
+            "images": [_image_json(i) for i in images],
+            "next_cursor": None,
+            "date_groups": [],
+        }
+    )
+
+
 @gallery_bp.route("/timeline", methods=["GET"])
 async def timeline():
     try:

backend/app/services/gallery_service.py

@@ -245,6 +245,27 @@ def _provenance_clause(post_id, artist_id):
     return None
 
 
+def _gallery_images(rows, artists: dict[int, dict]) -> list[GalleryImage]:
+    """Build GalleryImage list from (record, posted_at, eff_date) rows + the
+    artist hydration map. Shared by scroll() and similar()."""
+    return [
+        GalleryImage(
+            id=record.id,
+            path=record.path,
+            sha256=record.sha256,
+            mime=record.mime,
+            width=record.width,
+            height=record.height,
+            created_at=record.created_at,
+            effective_date=eff_date,
+            posted_at=posted_at,
+            thumbnail_url=thumbnail_url(record.thumbnail_path, record.sha256, record.mime),
+            artist=artists.get(record.id),
+        )
+        for record, posted_at, eff_date in rows
+    ]
+
+
 async def _artists_for(session, image_ids: list[int]) -> dict[int, dict]:
     """Map image_id -> {"name","slug"} via the canonical
     image_record.artist_id (FC-2d-vii-c). Bounded by page size."""
@@ -324,22 +345,7 @@ class GalleryService:
         artists = await _artists_for(
             self.session, [r[0].id for r in rows]
         )
-        images = [
-            GalleryImage(
-                id=record.id,
-                path=record.path,
-                sha256=record.sha256,
-                mime=record.mime,
-                width=record.width,
-                height=record.height,
-                created_at=record.created_at,
-                effective_date=eff_date,
-                posted_at=posted_at,
-                thumbnail_url=thumbnail_url(record.thumbnail_path, record.sha256, record.mime),
-                artist=artists.get(record.id),
-            )
-            for record, posted_at, eff_date in rows
-        ]
+        images = _gallery_images(rows, artists)
         return GalleryPage(
             images=images,
             next_cursor=next_cursor,
@@ -505,6 +511,49 @@ class GalleryService:
             date_min=dmin, date_max=dmax,
         )
 
+    async def similar(
+        self, image_id: int, limit: int = 100, *,
+        tag_ids: list[int] | None = None, artist_id: int | None = None,
+        media_type: str | None = None, platform: str | None = None,
+        untagged: bool = False, no_artist: bool = False,
+        date_from: datetime | None = None, date_to: datetime | None = None,
+    ) -> list[GalleryImage] | None:
+        """Visual "more like this": images ranked by cosine distance to
+        `image_id`'s SigLIP embedding (pgvector, HNSW-indexed — alembic 0036).
+        No ML inference here; the embedding was computed at import.
+
+        Returns None if the source image doesn't exist (→ 404), [] if it has
+        no embedding (a video / not-yet-embedded). Composes with the Phase-1/2
+        scope filters (AND) but REPLACES the date sort — always nearest-first,
+        bounded to `limit` (no cursor; distance-ranking has no date cursor).
+        """
+        if limit < 1 or limit > 200:
+            raise ValueError("limit must be between 1 and 200")
+        src = await self.session.get(ImageRecord, image_id)
+        if src is None:
+            return None
+        if src.siglip_embedding is None:
+            return []
+
+        distance = ImageRecord.siglip_embedding.cosine_distance(src.siglip_embedding)
+        eff = _effective_date_col()
+        stmt = select(ImageRecord, Post.post_date, eff.label("eff"))
+        stmt = _outer_join_primary_post(stmt)
+        stmt = stmt.where(
+            ImageRecord.siglip_embedding.is_not(None),
+            ImageRecord.id != image_id,
+        )
+        stmt = _apply_scope(
+            stmt, tag_ids=tag_ids, post_id=None,
+            artist_id=artist_id, media_type=media_type,
+            platform=platform, untagged=untagged, no_artist=no_artist,
+            date_from=date_from, date_to=date_to,
+        )
+        stmt = stmt.order_by(distance.asc()).limit(limit)
+        rows = (await self.session.execute(stmt)).all()
+        artists = await _artists_for(self.session, [r[0].id for r in rows])
+        return _gallery_images(rows, artists)
+
     async def get_image_with_tags(self, image_id: int) -> dict | None:
         record = await self.session.get(ImageRecord, image_id)
         if record is None:
@@ -542,6 +591,9 @@ class GalleryService:
             "height": record.height,
             "size_bytes": record.size_bytes,
             "integrity_status": record.integrity_status,
+            # Phase 3: lets the modal hide the "Related"/find-similar surface
+            # for images that have no embedding yet (videos / pending ML).
+            "has_embedding": record.siglip_embedding is not None,
             "created_at": record.created_at.isoformat(),
             "posted_at": posted_at.isoformat() if posted_at else None,
             "thumbnail_url": thumbnail_url(record.thumbnail_path, record.sha256, record.mime),

frontend/src/components/TopNav.vue

@@ -11,6 +11,8 @@
       <PipelineStatusChip />
     </div>
 
+    <!-- Desktop: inline links, centered. Hidden on mobile (see media query),
+         where they fold into the hamburger menu on the right. -->
     <nav class="fc-links">
       <RouterLink
         v-for="r in navRoutes"
@@ -20,9 +22,31 @@
       >{{ r.meta.title }}</RouterLink>
     </nav>
 
-    <!-- Per-view contextual actions teleport here (Showcase: Shuffle,
-         Gallery: Select). TopNav owns the slot, not its contents. -->
-    <div id="fc-nav-actions" class="fc-nav-actions" />
+    <div class="fc-nav-right">
+      <!-- Per-view contextual actions teleport here (Showcase: Shuffle,
+           Gallery: Select). TopNav owns the slot, not its contents. -->
+      <div id="fc-nav-actions" class="fc-nav-actions" />
+
+      <!-- Mobile nav: the link row collides with brand + actions below ~768px
+           (7+ links in one flex row), so collapse it into a menu. -->
+      <v-menu location="bottom end">
+        <template #activator="{ props: menuProps }">
+          <v-btn
+            v-bind="menuProps"
+            icon="mdi-menu" variant="text" size="small"
+            class="fc-nav-burger" aria-label="Menu"
+          />
+        </template>
+        <v-list density="compact" min-width="180">
+          <v-list-item
+            v-for="r in navRoutes"
+            :key="r.name"
+            :to="{ name: r.name }"
+            :title="r.meta.title"
+          />
+        </v-list>
+      </v-menu>
+    </div>
   </header>
 </template>
 
@@ -137,7 +161,7 @@ const health = computed(() => {
   align-items: center;
   flex-shrink: 0;
 }
-.fc-nav-actions {
+.fc-nav-right {
   flex: 1 1 0;
   min-width: 0;
   display: flex;
@@ -145,4 +169,22 @@ const health = computed(() => {
   justify-content: flex-end;
   gap: 0.5rem;
 }
+.fc-nav-actions {
+  display: flex;
+  align-items: center;
+  gap: 0.5rem;
+}
+/* The hamburger only exists on mobile; the inline links carry desktop. */
+.fc-nav-burger { display: none; }
+
+@media (max-width: 768px) {
+  .fc-topnav { gap: 0.5rem; padding: 0.6rem 0.75rem; }
+  /* Fold the link row into the hamburger menu. */
+  .fc-links { display: none; }
+  .fc-nav-burger { display: inline-flex; }
+}
+@media (max-width: 480px) {
+  /* Reclaim width on the smallest phones — the glyph alone still brands. */
+  .fc-brand__text { display: none; }
+}
 </style>

frontend/src/components/gallery/BulkEditorPanel.vue

@@ -186,7 +186,9 @@ async function onDeleteConfirm(token) {
 <style scoped>
 .fc-bulk-panel {
   position: fixed; top: 0; right: 0;
-  width: 320px; height: 100vh; z-index: 1100;
+  /* min(320px, 90vw): on phones the panel never swallows the whole screen —
+     leaves a sliver of the gallery visible behind it. */
+  width: min(320px, 90vw); height: 100vh; z-index: 1100;
   background: rgb(var(--v-theme-surface));
   border-left: 1px solid rgb(var(--v-theme-surface-light));
   box-shadow: -2px 0 16px rgba(0, 0, 0, 0.4);

frontend/src/components/gallery/GalleryFacetPanel.vue

@@ -143,4 +143,11 @@ onBeforeUnmount(() => { if (debounce) clearTimeout(debounce) })
 .fc-facets__empty { color: rgb(var(--v-theme-on-surface-variant)); font-size: 0.8rem; }
 .fc-facets__date { max-width: 160px; }
 .fc-facets__dash { color: rgb(var(--v-theme-on-surface-variant)); }
+
+/* Phones: let each facet group wrap and the side-by-side date inputs grow to
+   full width so they don't overflow a ~360px viewport. */
+@media (max-width: 480px) {
+  .fc-facets__group { flex-wrap: wrap; }
+  .fc-facets__date { max-width: none; flex: 1 1 9rem; }
+}
 </style>

frontend/src/components/gallery/GalleryFilterBar.vue

@@ -38,6 +38,12 @@
         prepend-icon="mdi-account"
         @click:close="clearArtist"
       >{{ store.artistLabel || `Artist #${store.filter.artist_id}` }}</v-chip>
+      <v-chip
+        v-if="store.filter.similar_to"
+        size="small" closable color="accent" variant="tonal"
+        prepend-icon="mdi-image-multiple"
+        @click:close="clearSimilar"
+      >Similar to #{{ store.filter.similar_to }}</v-chip>
     </div>
 
     <v-spacer />
@@ -52,7 +58,9 @@
       <v-btn value="video" size="small">Videos</v-btn>
     </v-btn-toggle>
 
+    <!-- Sort is meaningless in similar-mode (results are distance-ranked). -->
     <v-select
+      v-if="!store.filter.similar_to"
       :model-value="store.filter.sort"
       :items="SORTS"
       density="compact" hide-details variant="outlined"
@@ -114,6 +122,7 @@ const hasActiveFilters = computed(() =>
   store.filter.artist_id != null ||
   store.filter.media_type != null ||
   store.filter.sort !== 'newest' ||
+  store.filter.similar_to != null ||
   hasRefineFilters.value
 )
 
@@ -190,6 +199,7 @@ function clearArtist() {
   store.noteArtistLabel(null)
   pushFilter((n) => { n.artist_id = null })
 }
+function clearSimilar() { pushFilter((n) => { n.similar_to = null }) }
 function setMedia(m) { pushFilter((n) => { n.media_type = m }) }
 function setSort(s) { pushFilter((n) => { n.sort = s }) }
 function clearAll() { router.push({ name: 'gallery', query: {} }) }
@@ -207,7 +217,7 @@ function pushFilter(mutate) {
 
 <style scoped>
 /* The whole chrome (bar row + expandable refine panel) is one sticky,
-   hazey block pinned directly under the 64px TopNav and continuous with it. */
+   frosted block pinned directly under the 64px TopNav and continuous with it. */
 .fc-filterbar-wrap {
   position: sticky;
   top: 64px;
@@ -217,9 +227,18 @@ function pushFilter(mutate) {
      and a gap shows through when scrolled to the top. */
   margin-top: -8px;
   margin-bottom: 12px;
-  /* Same hazey obsidian (#14171A = 20,23,26) + blur as the TopNav so the two
-     read as one piece of chrome; content scrolls under both. */
-  background: rgba(20, 23, 26, 0.55);
+  /* EXACT same gradiated obsidian (#14171A = 20,23,26) frost as the TopNav so
+     the two read as one continuous piece of chrome — images scroll visibly
+     under both. The nav's gradient fades to transparent at ITS bottom; this
+     bar re-darkens at its top, so a faint seam (the page/image showing through
+     the nav's transparent edge) separates them when scrolled to the very top,
+     while under-scroll they frost as one. */
+  background: linear-gradient(
+    to bottom,
+    rgba(20, 23, 26, 0.92) 0%,
+    rgba(20, 23, 26, 0.65) 60%,
+    rgba(20, 23, 26, 0) 100%
+  );
   backdrop-filter: blur(2px);
   -webkit-backdrop-filter: blur(2px);
 }
@@ -239,4 +258,12 @@ function pushFilter(mutate) {
 .fc-filterbar__search { max-width: 320px; min-width: 200px; }
 .fc-filterbar__chips { display: flex; align-items: center; gap: 6px; flex-wrap: wrap; }
 .fc-filterbar__sort { max-width: 150px; }
+
+/* Phones: the search's 200px min-width jams the wrapping bar. Give search its
+   own full-width row and let sort grow; everything else wraps under it. */
+@media (max-width: 600px) {
+  .fc-filterbar { gap: 8px; }
+  .fc-filterbar__search { min-width: 100%; max-width: none; }
+  .fc-filterbar__sort { max-width: none; flex: 1 1 auto; }
+}
 </style>

frontend/src/components/modal/ImageViewer.vue

@@ -51,6 +51,9 @@
         <aside v-if="modal.current" class="fc-viewer__side">
           <ProvenancePanel />
           <TagPanel />
+          <!-- Non-blocking: fetches its own similar set after the modal is up;
+               collapses silently if empty/slow/failed (see RelatedStrip). -->
+          <RelatedStrip />
         </aside>
       </div>
     </div>
@@ -65,6 +68,7 @@ import ImageCanvas from './ImageCanvas.vue'
 import VideoCanvas from './VideoCanvas.vue'
 import TagPanel from './TagPanel.vue'
 import ProvenancePanel from './ProvenancePanel.vue'
+import RelatedStrip from './RelatedStrip.vue'
 
 const emit = defineEmits(['close'])
 

frontend/src/components/modal/RelatedStrip.vue

@@ -0,0 +1,133 @@
+<template>
+  <!-- Collapses entirely unless the source has an embedding AND we're loading
+       or have results — so a slow/empty/failed fetch leaves no trace and never
+       affects the modal. -->
+  <div v-if="show" class="fc-related">
+    <div class="fc-related__head">
+      <span class="fc-related__title">Related</span>
+      <v-btn
+        size="x-small" variant="text" color="accent"
+        :disabled="loading || !results.length"
+        @click="seeAll"
+      >See all similar</v-btn>
+    </div>
+    <div class="fc-related__row">
+      <template v-if="loading">
+        <div v-for="n in 6" :key="n" class="fc-related__skel" />
+      </template>
+      <button
+        v-for="img in results" :key="img.id"
+        class="fc-related__item" type="button"
+        @click="openImage(img.id)"
+      >
+        <img :src="img.thumbnail_url" :alt="`image ${img.id}`" loading="lazy" />
+      </button>
+    </div>
+  </div>
+</template>
+
+<script setup>
+import { computed, onBeforeUnmount, ref, watch } from 'vue'
+import { useRouter } from 'vue-router'
+import { useApi } from '../../composables/useApi.js'
+import { useModalStore } from '../../stores/modal.js'
+
+// Deferred so the modal's main image gets network/decode priority — the strip
+// is a nice-to-have and must never block or slow the modal load.
+const DEFER_MS = 200
+const STRIP_LIMIT = 12
+
+const api = useApi()
+const router = useRouter()
+const modal = useModalStore()
+
+const results = ref([])
+const loading = ref(false)
+
+const hasEmbedding = computed(() => modal.current?.has_embedding === true)
+const show = computed(() => hasEmbedding.value && (loading.value || results.value.length > 0))
+
+let seq = 0
+let timer = null
+
+async function fetchSimilar(id) {
+  const mine = ++seq
+  loading.value = true
+  results.value = []
+  try {
+    const body = await api.get('/api/gallery/similar', {
+      params: { similar_to: id, limit: STRIP_LIMIT },
+    })
+    if (mine !== seq) return
+    results.value = body.images || []
+  } catch {
+    if (mine === seq) results.value = []  // quietly collapse on error
+  } finally {
+    if (mine === seq) loading.value = false
+  }
+}
+
+// Re-fetch whenever the modal lands on a new embedded image. modal.current is
+// null while the next image loads, so this also clears the strip during
+// prev/next nav and repopulates once the new payload arrives.
+watch(
+  () => (hasEmbedding.value ? modal.current?.id : null),
+  (id) => {
+    if (timer) { clearTimeout(timer); timer = null }
+    seq++              // cancel any in-flight fetch
+    results.value = []
+    loading.value = false
+    if (!id) return
+    timer = setTimeout(() => fetchSimilar(id), DEFER_MS)
+  },
+  { immediate: true },
+)
+onBeforeUnmount(() => { if (timer) clearTimeout(timer) })
+
+function openImage(id) {
+  modal.open(id)
+}
+
+function seeAll() {
+  const id = modal.current?.id
+  if (!id) return
+  modal.close()
+  router.push({ name: 'gallery', query: { similar_to: String(id) } })
+}
+</script>
+
+<style scoped>
+.fc-related {
+  padding: 12px;
+  border-top: 1px solid rgb(var(--v-theme-surface-light));
+}
+.fc-related__head {
+  display: flex; align-items: center; justify-content: space-between;
+  margin-bottom: 8px;
+}
+.fc-related__title {
+  font-size: 0.7rem; text-transform: uppercase; letter-spacing: 0.06em;
+  color: rgb(var(--v-theme-on-surface-variant));
+}
+.fc-related__row {
+  display: grid;
+  grid-template-columns: repeat(4, 1fr);
+  gap: 6px;
+}
+.fc-related__item {
+  display: block; padding: 0; border: 0; background: none;
+  cursor: pointer; border-radius: 4px; overflow: hidden;
+  aspect-ratio: 1; width: 100%;
+}
+.fc-related__item img {
+  width: 100%; height: 100%; object-fit: cover; display: block;
+  background: rgb(var(--v-theme-surface-light));
+  transition: transform 0.2s ease, filter 0.2s ease;
+}
+.fc-related__item:hover img { transform: scale(1.05); filter: brightness(1.1); }
+.fc-related__skel {
+  aspect-ratio: 1; border-radius: 4px;
+  background: rgb(var(--v-theme-surface-light));
+  opacity: 0.5;
+}
+</style>

frontend/src/components/posts/PostsFilterBar.vue

@@ -13,7 +13,7 @@
       clearable
       no-filter
       return-object
-      style="min-width: 240px"
+      class="fc-posts-filters__artist"
       @update:search="onArtistSearch"
       @update:model-value="onArtistPicked"
     />
@@ -25,7 +25,7 @@
       density="compact"
       hide-details
       clearable
-      style="min-width: 180px"
+      class="fc-posts-filters__platform"
       @update:model-value="emitFilters"
     />
 
@@ -135,6 +135,14 @@ watch(() => props.platform, (val) => {
   display: flex;
   gap: 0.75rem;
   align-items: center;
+  flex-wrap: wrap;
   padding-bottom: 1rem;
 }
+.fc-posts-filters__artist { min-width: 240px; flex: 1 1 240px; max-width: 360px; }
+.fc-posts-filters__platform { min-width: 180px; flex: 1 1 180px; max-width: 240px; }
+/* Phones: each field takes a full-width row instead of overflowing. */
+@media (max-width: 600px) {
+  .fc-posts-filters__artist,
+  .fc-posts-filters__platform { min-width: 100%; max-width: none; flex-basis: 100%; }
+}
 </style>

frontend/src/components/subscriptions/SubscriptionsTab.vue

@@ -26,14 +26,14 @@
         :items="STATUS_OPTIONS"
         :disabled="needsAttention"
         density="compact" variant="outlined" hide-details
-        style="max-width: 180px"
+        class="fc-subs__status"
       />
       <v-text-field
         v-model="search"
         density="compact" variant="outlined" hide-details clearable
         prepend-inner-icon="mdi-magnify"
         placeholder="Search subscriptions"
-        style="max-width: 320px"
+        class="fc-subs__search"
       />
     </div>
 
@@ -568,6 +568,14 @@ async function bulkDelete() {
   padding: 8px 0 1rem;
 }
 .fc-subs__bar .v-chip { cursor: pointer; }
+.fc-subs__status { max-width: 180px; }
+.fc-subs__search { max-width: 320px; flex: 1 1 200px; }
+/* Phones: status + search each take a full-width row; drop the spacer that
+   would otherwise eat a row pushing them around. */
+@media (max-width: 600px) {
+  .fc-subs__status, .fc-subs__search { max-width: none; flex-basis: 100%; }
+  .fc-subs__bar :deep(.v-spacer) { display: none; }
+}
 .fc-subs__loading, .fc-subs__empty {
   display: flex; justify-content: center; padding: 2rem;
   color: rgb(var(--v-theme-on-surface-variant));

frontend/src/stores/gallery.js

@@ -27,6 +27,9 @@ export const useGalleryStore = defineStore('gallery', () => {
     // Phase-2 faceted refine params.
     platform: null, untagged: false, no_artist: false,
     date_from: null, date_to: null,
+    // Phase-3 visual similarity: when set, the gallery is in "similar mode" —
+    // ranked by cosine distance to this image, bounded top-N, no cursor.
+    similar_to: null,
   })
 
   // Live facet counts for the refine panel; fetched on-demand (panel open +
@@ -84,6 +87,39 @@ export const useGalleryStore = defineStore('gallery', () => {
     }
   }
 
+  // Visual "more like this": ranked top-N by cosine distance, scope filters
+  // composed (AND). No cursor / no timeline — bounded result set.
+  async function loadSimilar() {
+    inflight.cancel()
+    images.value = []
+    dateGroups.value = []
+    nextCursor.value = null
+    timelineBuckets.value = []
+    loading.value = true
+    error.value = null
+    const t = inflight.claim()
+    try {
+      const f = filter.value
+      const params = { similar_to: f.similar_to, limit: 100 }
+      if (f.tag_ids.length) params.tag_id = f.tag_ids.join(',')
+      if (f.artist_id) params.artist_id = f.artist_id
+      if (f.media_type) params.media = f.media_type
+      if (f.platform) params.platform = f.platform
+      if (f.untagged) params.untagged = '1'
+      if (f.no_artist) params.no_artist = '1'
+      if (f.date_from) params.date_from = f.date_from
+      if (f.date_to) params.date_to = f.date_to
+      const body = await api.get('/api/gallery/similar', { params })
+      if (!t.isCurrent()) return
+      images.value = body.images
+      // ranked + bounded → no next page (nextCursor stays null → hasMore false)
+    } catch (e) {
+      error.value = e.message
+    } finally {
+      if (t.isCurrent()) loading.value = false
+    }
+  }
+
   async function jumpTo(year, month) {
     // Rapid timeline-jump clicks need the same race guard as
     // loadMore — first jump's late body could clobber the second
@@ -150,9 +186,15 @@ export const useGalleryStore = defineStore('gallery', () => {
       no_artist: _truthy(q.no_artist),
       date_from: _parseDate(q.date_from),
       date_to: _parseDate(q.date_to),
+      similar_to: _toId(q.similar_to),
+    }
+    if (filter.value.similar_to) {
+      // Similar mode: ranked, no timeline scroll.
+      await loadSimilar()
+    } else {
+      await loadInitial()
+      await loadTimeline()
     }
-    await loadInitial()
-    await loadTimeline()
     _resolveLabels()
   }
 
@@ -200,7 +242,7 @@ export const useGalleryStore = defineStore('gallery', () => {
     images, dateGroups, hasMore, isEmpty, loading, error,
     filter, tagLabels, artistLabel, timelineBuckets, timelineLoading,
     facets, facetsLoading,
-    loadInitial, loadMore, loadTimeline, jumpTo, loadFacets,
+    loadInitial, loadMore, loadTimeline, jumpTo, loadFacets, loadSimilar,
     applyFilterFromQuery, noteTagLabel, noteArtistLabel,
   }
 })
@@ -213,6 +255,7 @@ export function cloneFilter(f) {
     tag_ids: [...f.tag_ids], artist_id: f.artist_id, media_type: f.media_type,
     sort: f.sort, platform: f.platform, untagged: f.untagged,
     no_artist: f.no_artist, date_from: f.date_from, date_to: f.date_to,
+    similar_to: f.similar_to,
   }
 }
 
@@ -227,6 +270,7 @@ export function filterToQuery(f) {
   if (f.no_artist) q.no_artist = '1'
   if (f.date_from) q.date_from = f.date_from
   if (f.date_to) q.date_to = f.date_to
+  if (f.similar_to) q.similar_to = String(f.similar_to)
   return q
 }
 

frontend/src/stores/showcase.js

@@ -24,7 +24,8 @@ import { preloadImage } from '../utils/preloadImage.js'
 // fetch + decode (a cold TABLESAMPLE is a separate, query-side concern);
 // everything after it is buffer-smoothed.
 const PAGE = 3
-const CADENCE_MS = 80          // floor between fully-loaded reveals
+const CADENCE_MS = 160         // floor between fully-loaded reveals (doubled
+                              // 2026-06-04 — slower, more deliberate cadence)
 const PRIME = 6                // items buffered before the drain starts
 const BUFFER_TARGET = 30       // producer tops the queue up to this
 const BUFFER_MIN = 12          // ...and refills once the queue dips below this

frontend/src/views/ArtistsView.vue

@@ -76,7 +76,9 @@ onMounted(async () => {
 }
 .fc-artists__grid {
   display: grid;
-  grid-template-columns: repeat(auto-fill, minmax(440px, 1fr));
+  /* min(440px, 100%) so a card never exceeds the viewport — on phones the
+     min-track collapses to 100% (single column) instead of overflowing. */
+  grid-template-columns: repeat(auto-fill, minmax(min(440px, 100%), 1fr));
   gap: 12px;
 }
 .fc-artists__sentinel {

frontend/src/views/GalleryView.vue

@@ -16,7 +16,10 @@
         <EmptyState v-if="store.isEmpty" />
         <GalleryGrid v-else @open="openImage" />
       </div>
-      <TimelineSidebar v-if="store.images.length > 0" class="fc-gallery-layout__sidebar" />
+      <TimelineSidebar
+        v-if="store.images.length > 0 && store.filter.similar_to == null"
+        class="fc-gallery-layout__sidebar"
+      />
     </div>
 
     <BulkEditorPanel />
@@ -68,4 +71,9 @@ function openImage(id) {
   .fc-gallery-layout { flex-direction: column-reverse; }
   .fc-gallery-layout__sidebar { width: 100%; max-height: 200px; }
 }
+/* Phones: the year/month timeline strip eats vertical space and reads poorly
+   as a horizontal band — drop it; the gallery scroll is the primary nav here. */
+@media (max-width: 600px) {
+  .fc-gallery-layout__sidebar { display: none; }
+}
 </style>

frontend/test/components/galleryRelatedStrip.spec.js

@@ -0,0 +1,73 @@
+// @vitest-environment happy-dom
+import { describe, it, expect, vi, beforeEach, afterEach } from 'vitest'
+import { flushPromises } from '@vue/test-utils'
+
+import RelatedStrip from '../../src/components/modal/RelatedStrip.vue'
+import { useModalStore } from '../../src/stores/modal.js'
+import { freshPinia, mountComponent } from '../support/mountComponent.js'
+
+function stubFetch(handler) {
+  globalThis.fetch = vi.fn(async (url) => {
+    const { status, body } = handler(url)
+    return {
+      ok: status >= 200 && status < 300,
+      status, statusText: String(status),
+      text: async () => JSON.stringify(body),
+    }
+  })
+}
+
+describe('RelatedStrip (modal "more like this")', () => {
+  beforeEach(() => vi.useFakeTimers())
+  afterEach(() => { vi.useRealTimers(); vi.restoreAllMocks() })
+
+  it('stays hidden and never fetches when the image has no embedding', async () => {
+    const pinia = freshPinia()
+    useModalStore().current = { id: 1, has_embedding: false }
+    const fetchSpy = vi.fn()
+    globalThis.fetch = fetchSpy
+    const w = mountComponent(RelatedStrip, { pinia })
+    await vi.advanceTimersByTimeAsync(500)
+    expect(fetchSpy).not.toHaveBeenCalled()
+    expect(w.find('.fc-related').exists()).toBe(false)
+  })
+
+  it('deferred-fetches and renders similar thumbs for an embedded image', async () => {
+    const pinia = freshPinia()
+    useModalStore().current = { id: 1, has_embedding: true }
+    stubFetch(() => ({
+      status: 200,
+      body: { images: [{ id: 2, thumbnail_url: '/t2' }, { id: 3, thumbnail_url: '/t3' }] },
+    }))
+    const w = mountComponent(RelatedStrip, { pinia })
+    // Nothing before the defer elapses (modal image gets priority).
+    expect(globalThis.fetch).not.toHaveBeenCalled()
+    await vi.advanceTimersByTimeAsync(250)
+    await flushPromises()
+    expect(globalThis.fetch).toHaveBeenCalledTimes(1)
+    expect(w.findAll('.fc-related__item').length).toBe(2)
+  })
+
+  it('collapses silently when the similar fetch returns nothing', async () => {
+    const pinia = freshPinia()
+    useModalStore().current = { id: 1, has_embedding: true }
+    stubFetch(() => ({ status: 200, body: { images: [] } }))
+    const w = mountComponent(RelatedStrip, { pinia })
+    await vi.advanceTimersByTimeAsync(250)
+    await flushPromises()
+    expect(w.find('.fc-related').exists()).toBe(false)
+  })
+
+  it('clicking a thumb opens that image in the modal', async () => {
+    const pinia = freshPinia()
+    const modal = useModalStore()
+    modal.current = { id: 1, has_embedding: true }
+    const openSpy = vi.spyOn(modal, 'open').mockResolvedValue()
+    stubFetch(() => ({ status: 200, body: { images: [{ id: 7, thumbnail_url: '/t7' }] } }))
+    const w = mountComponent(RelatedStrip, { pinia })
+    await vi.advanceTimersByTimeAsync(250)
+    await flushPromises()
+    await w.find('.fc-related__item').trigger('click')
+    expect(openSpy).toHaveBeenCalledWith(7)
+  })
+})

frontend/test/gallery.spec.js

@@ -122,6 +122,28 @@ describe('gallery store: composable filter', () => {
     expect(s.facets.total).toBe(4)
   })
 
+  it('similar_to routes applyFilterFromQuery to the /similar endpoint, not scroll', async () => {
+    const s = useGalleryStore()
+    const urls = []
+    stubFetch((url) => {
+      urls.push(url)
+      if (url.includes('/api/gallery/similar')) {
+        return { status: 200, body: { images: [{ id: 9 }], next_cursor: null, date_groups: [] } }
+      }
+      return { status: 200, body: EMPTY }
+    })
+    await s.applyFilterFromQuery({ similar_to: '5', tag_id: '3' })
+    expect(s.filter.similar_to).toBe(5)
+    const sim = decodeURIComponent(urls.find((u) => u.includes('/api/gallery/similar')))
+    expect(sim).toContain('similar_to=5')
+    expect(sim).toContain('limit=100')
+    expect(sim).toContain('tag_id=3')          // scope composes
+    expect(s.images.map((i) => i.id)).toEqual([9])
+    expect(s.hasMore).toBe(false)              // ranked + bounded → no pages
+    expect(urls.some((u) => u.includes('/api/gallery/scroll'))).toBe(false)
+    expect(urls.some((u) => u.includes('/api/gallery/timeline'))).toBe(false)
+  })
+
   it('loadInitial issues exactly one scroll request at the initial limit', async () => {
     const s = useGalleryStore()
     const urls = []
@@ -154,6 +176,11 @@ describe('filterToQuery / cloneFilter', () => {
     expect(q.sort).toBeUndefined()  // newest is the default → omitted
   })
 
+  it('serializes similar_to', () => {
+    expect(filterToQuery({ tag_ids: [], similar_to: 42 }).similar_to).toBe('42')
+    expect(filterToQuery({ tag_ids: [], similar_to: null }).similar_to).toBeUndefined()
+  })
+
   it('cloneFilter copies refine fields and detaches tag_ids', () => {
     const orig = {
       tag_ids: [1], artist_id: 2, media_type: 'image', sort: 'oldest',

frontend/test/showcase.spec.js

@@ -46,8 +46,8 @@ describe('showcase store: buffered cascade', () => {
     stubShowcase()
     const s = useShowcaseStore()
     const p = s.loadInitial()
-    // Past INITIAL_COUNT (60) × CADENCE (80ms) plus fetch microtasks.
-    await vi.advanceTimersByTimeAsync(6000)
+    // Past INITIAL_COUNT (60) × CADENCE (160ms = 9.6s) plus fetch microtasks.
+    await vi.advanceTimersByTimeAsync(12000)
     await p
     expect(s.images.length).toBe(60)
     const ids = s.images.map((i) => i.id)
@@ -65,7 +65,7 @@ describe('showcase store: buffered cascade', () => {
     // the cadence — a 1s window must not dump the whole buffer at once.
     expect(early).toBeGreaterThan(0)
     expect(early).toBeLessThan(60)
-    await vi.advanceTimersByTimeAsync(6000)
+    await vi.advanceTimersByTimeAsync(12000)
     await p
     expect(s.images.length).toBe(60)
   })
@@ -80,7 +80,7 @@ describe('showcase store: buffered cascade', () => {
     await vi.advanceTimersByTimeAsync(1000)
     expect(s.images.length).toBe(0)   // gated on the un-decoded first image
     release()
-    await vi.advanceTimersByTimeAsync(6000)
+    await vi.advanceTimersByTimeAsync(12000)
     await p
     expect(s.images.length).toBe(60)  // cascade proceeds once it decodes
   })

tests/test_gallery_similar.py

@@ -0,0 +1,134 @@
+"""Phase-3 visual "more like this" — pgvector cosine ranking over the
+precomputed SigLIP image embeddings. No query-time ML inference."""
+
+from datetime import UTC, datetime, timedelta
+
+import pytest
+
+from backend.app.models import ImageRecord, Tag, TagKind
+from backend.app.models.tag import image_tag
+from backend.app.services.gallery_service import GalleryService
+
+pytestmark = pytest.mark.integration
+
+
+def _vec(*head):
+    """A 1152-dim embedding with the given leading values, rest zero. Cosine
+    distance to _vec(1,0) grows as the 2nd component grows, so callers can
+    order fixtures deterministically by direction."""
+    v = [0.0] * 1152
+    for i, x in enumerate(head):
+        v[i] = float(x)
+    return v
+
+
+async def _img(db, n, emb):
+    rec = ImageRecord(
+        path=f"/images/sim/{n}.jpg", sha256=f"e{n:063d}",
+        size_bytes=1, mime="image/jpeg", width=1, height=1,
+        origin="imported_filesystem", integrity_status="unknown",
+        siglip_embedding=emb,
+    )
+    base = datetime(2026, 1, 1, 12, 0, tzinfo=UTC)
+    rec.created_at = base - timedelta(minutes=n)
+    rec.effective_date = rec.created_at
+    db.add(rec)
+    await db.flush()
+    return rec
+
+
+@pytest.mark.asyncio
+async def test_similar_ranks_nearest_first(db):
+    src = await _img(db, 1, _vec(1, 0))
+    near = await _img(db, 2, _vec(1, 0.05))   # almost same direction
+    mid = await _img(db, 3, _vec(1, 1))       # 45°
+    far = await _img(db, 4, _vec(0, 1))       # orthogonal
+    svc = GalleryService(db)
+    res = await svc.similar(src.id, limit=10)
+    assert [i.id for i in res] == [near.id, mid.id, far.id]  # self excluded
+
+
+@pytest.mark.asyncio
+async def test_similar_excludes_null_embeddings(db):
+    src = await _img(db, 1, _vec(1, 0))
+    have = await _img(db, 2, _vec(1, 0.1))
+    await _img(db, 3, None)  # un-embedded (e.g. a video) → excluded
+    svc = GalleryService(db)
+    res = await svc.similar(src.id, limit=10)
+    assert [i.id for i in res] == [have.id]
+
+
+@pytest.mark.asyncio
+async def test_similar_source_without_embedding_returns_empty(db):
+    src = await _img(db, 1, None)
+    await _img(db, 2, _vec(1, 0))
+    svc = GalleryService(db)
+    assert await svc.similar(src.id, limit=10) == []
+
+
+@pytest.mark.asyncio
+async def test_similar_missing_source_returns_none(db):
+    svc = GalleryService(db)
+    assert await svc.similar(99999, limit=10) is None
+
+
+@pytest.mark.asyncio
+async def test_similar_composes_with_tag_filter(db):
+    src = await _img(db, 1, _vec(1, 0))
+    await _img(db, 2, _vec(1, 0.02))     # nearest, but untagged
+    tagged = await _img(db, 3, _vec(1, 0.6))  # farther, but carries the tag
+    tag = Tag(name="t", kind=TagKind.general)
+    db.add(tag)
+    await db.flush()
+    await db.execute(image_tag.insert().values(
+        image_record_id=tagged.id, tag_id=tag.id, source="manual"))
+    svc = GalleryService(db)
+    res = await svc.similar(src.id, limit=10, tag_ids=[tag.id])
+    assert [i.id for i in res] == [tagged.id]  # scope AND-narrows the ranked set
+
+
+@pytest.mark.asyncio
+async def test_similar_respects_limit(db):
+    src = await _img(db, 1, _vec(1, 0))
+    for n in range(2, 7):
+        await _img(db, n, _vec(1, 0.1 * n))
+    svc = GalleryService(db)
+    res = await svc.similar(src.id, limit=2)
+    assert len(res) == 2
+
+
+# --- API ---
+
+@pytest.mark.asyncio
+async def test_api_similar_endpoint(client, db):
+    src = await _img(db, 1, _vec(1, 0))
+    near = await _img(db, 2, _vec(1, 0.05))
+    await db.commit()
+    resp = await client.get(f"/api/gallery/similar?similar_to={src.id}&limit=10")
+    assert resp.status_code == 200
+    body = await resp.get_json()
+    assert [i["id"] for i in body["images"]] == [near.id]
+    assert body["next_cursor"] is None
+
+
+@pytest.mark.asyncio
+async def test_api_similar_404_when_source_missing(client):
+    resp = await client.get("/api/gallery/similar?similar_to=99999")
+    assert resp.status_code == 404
+
+
+@pytest.mark.asyncio
+async def test_api_similar_requires_param(client):
+    resp = await client.get("/api/gallery/similar")
+    assert resp.status_code == 400
+
+
+@pytest.mark.asyncio
+async def test_image_detail_reports_has_embedding(client, db):
+    embedded = await _img(db, 1, _vec(1, 0))
+    plain = await _img(db, 2, None)
+    await db.commit()
+    e = await (await client.get(f"/api/gallery/image/{embedded.id}")).get_json()
+    p = await (await client.get(f"/api/gallery/image/{plain.id}")).get_json()
+    assert e["has_embedding"] is True
+    assert p["has_embedding"] is False