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>

backend/app/services/gallery_service.py

@@ -237,6 +237,15 @@ class GalleryService:
         )
         tags = (await self.session.execute(tag_stmt)).scalars().all()
         neighbors = await self._neighbors(record)
+        # Direct artist FK — used by the modal's ProvenancePanel as a
+        # fallback when ImageProvenance is empty (i.e., filesystem-
+        # imported images without a post-track provenance row). The
+        # source of truth for richer post-level data is still
+        # ImageProvenance/Post; this is just the "we at least know who
+        # made it" line.
+        artist = None
+        if record.artist_id is not None:
+            artist = await self.session.get(Artist, record.artist_id)
         return {
             "id": record.id,
             "path": record.path,
@@ -249,6 +258,10 @@ class GalleryService:
             "created_at": record.created_at.isoformat(),
             "thumbnail_url": thumbnail_url(record.sha256, record.mime),
             "image_url": f"/images/{record.path.split('/images/', 1)[-1]}",
+            "artist": (
+                {"id": artist.id, "name": artist.name, "slug": artist.slug}
+                if artist is not None else None
+            ),
             "tags": [
                 {
                     "id": t.id,