feat(explore): exclude WIP-tagged work from the Explore rabbit-hole

Explore's neighbour grid (/api/gallery/similar → gallery_service.similar) now
takes an Explore-only exclude_wip flag that drops `wip` system-tagged images
from the candidates, alongside the banner/editor presentation tags. The
gallery's own "similar" button is unchanged (keeps wip, #1274) — only the
Explore store passes exclude_wip=1. The anchor itself may still be a WIP; only
neighbours are filtered.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

backend/app/api/gallery.py

@@ -145,6 +145,9 @@ async def similar():
         filters, _sort = _parse_filters()
     except (KeyError, ValueError):
         return jsonify({"error": "similar_to query param required"}), 400
+    # Explore passes exclude_wip=1 to also drop work-in-progress from the
+    # rabbit-hole; the gallery's own "similar" button omits it (keeps wip, #1274).
+    exclude_wip = request.args.get("exclude_wip") in ("1", "true", "True")
     # post_id is the exclusive post-detail view — not a similarity scope.
     # include_hidden is a gallery-browse flag; similar() has its OWN presentation
     # exclusion (a similarity-quality concern, #1274), so drop it here (#141).
@@ -154,7 +157,8 @@ async def similar():
     async with get_session() as session:
         svc = GalleryService(session)
         try:
-            images = await svc.similar(image_id=similar_to, limit=limit, **scope)
+            images = await svc.similar(
+                image_id=similar_to, limit=limit, exclude_wip=exclude_wip, **scope)
         except ValueError as exc:
             return jsonify({"error": str(exc)}), 400
     if images is None:

backend/app/models/tag.py

@@ -48,6 +48,10 @@ class TagKind(StrEnum):
 # content. `wip` is real art: only the training pipelines exclude it.
 SYSTEM_TAG_NAMES = ("wip", "banner", "editor screenshot")
 PRESENTATION_SYSTEM_TAGS = ("banner", "editor screenshot")
+# `wip` marks real-but-unfinished art. It's kept in the gallery's own "similar"
+# results (#1274), but the Explore rabbit-hole opts to hide it (exclude_wip) so a
+# browse doesn't keep surfacing work-in-progress (operator, 2026-07-08).
+WIP_SYSTEM_TAG = "wip"
 
 image_tag = Table(
     "image_tag",

backend/app/services/gallery_service.py

@@ -31,7 +31,7 @@ from ..models import (
     Tag,
     TagPositiveConfirmation,
 )
-from ..models.tag import PRESENTATION_SYSTEM_TAGS, image_tag
+from ..models.tag import PRESENTATION_SYSTEM_TAGS, WIP_SYSTEM_TAG, image_tag
 from .pagination import decode_cursor, encode_cursor
 from .tag_query import (
     fandom_join_alias,
@@ -715,6 +715,7 @@ class GalleryService:
         platform: str | None = None,
         untagged: bool = False, no_artist: bool = False,
         date_from: datetime | None = None, date_to: datetime | None = None,
+        exclude_wip: bool = False,
     ) -> list[GalleryImage] | None:
         """Visual "more like this": images near `image_id`'s SigLIP embedding
         (pgvector, HNSW-indexed — alembic 0036), then DIVERSIFIED so the result
@@ -751,14 +752,18 @@ class GalleryService:
         # Presentation images (banner / editor-screenshot system tags, #128)
         # cluster on UI chrome rather than content, so near any one of them
         # they'd fill the grid. Excluded from CANDIDATES only — the anchor
-        # itself may be a banner, and `wip` stays surfaced (real art; only
-        # the training pipelines exclude it).
+        # itself may be a banner. `wip` stays surfaced here by default (real art;
+        # only the training pipelines exclude it), but the Explore rabbit-hole
+        # passes exclude_wip to also drop work-in-progress (operator, 2026-07-08).
+        excluded_system_tags = PRESENTATION_SYSTEM_TAGS
+        if exclude_wip:
+            excluded_system_tags = (*PRESENTATION_SYSTEM_TAGS, WIP_SYSTEM_TAG)
         presentation = (
             select(image_tag.c.image_record_id)
             .join(Tag, Tag.id == image_tag.c.tag_id)
             .where(
                 Tag.is_system.is_(True),
-                Tag.name.in_(PRESENTATION_SYSTEM_TAGS),
+                Tag.name.in_(excluded_system_tags),
             )
         )
         stmt = stmt.where(