fc-3g-ext: IR Post/Provenance restore (tag_apply phase 4) + modal artist fallback

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

frontend/src/components/modal/ProvenancePanel.vue

@@ -43,6 +43,21 @@
           class="fc-prov__desc" v-html="e.post.description_html"
         />
       </article>
+
+      <!-- Fallback: image has artist_id set (folder-derived from
+           filesystem import or set by tag_apply) but no ImageProvenance
+           row exists. Show a minimal "by <artist>" line so the modal
+           isn't blank for IR-imported images that aren't in any post. -->
+      <article
+        v-if="showArtistFallback"
+        class="fc-prov__card"
+      >
+        <div class="fc-prov__meta">
+          <RouterLink :to="`/artist/${fallbackArtist.slug}`">
+            by {{ fallbackArtist.name }}
+          </RouterLink>
+        </div>
+      </article>
     </template>
 
     <div v-if="attachments.length" class="fc-prov__attach">
@@ -79,13 +94,27 @@ const state = computed(() =>
   modal.currentImageId == null ? null : prov.imageProv(modal.currentImageId)
 )
 
-// Show the panel while loading or on error, or when there is >=1 entry.
-// Hide entirely when the image has zero provenance.
+const fallbackArtist = computed(() => modal.current?.artist || null)
+
+const showArtistFallback = computed(() => {
+  const st = state.value
+  // Only show the fallback when provenance is genuinely empty (no
+  // entries, not loading, no error) AND the image has a direct
+  // artist_id we can surface.
+  if (!st || st.loading || st.error) return false
+  if (Array.isArray(st.entries) && st.entries.length > 0) return false
+  return fallbackArtist.value != null
+})
+
+// Show the panel while loading or on error, when there is >=1 entry,
+// or when the artist fallback applies (image_record.artist_id set but
+// no ImageProvenance row, e.g. filesystem-imported IR images).
 const show = computed(() => {
   const st = state.value
   if (!st) return false
   if (st.loading || st.error) return true
-  return Array.isArray(st.entries) && st.entries.length > 0
+  if (Array.isArray(st.entries) && st.entries.length > 0) return true
+  return showArtistFallback.value
 })
 
 const attachments = computed(() => state.value?.attachments || [])