feat(provenance): post_id/artist_id gallery filters via EXISTS (mutually exclusive)

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

backend/app/api/gallery.py

@@ -17,11 +17,18 @@ async def scroll():
         return jsonify({"error": "limit must be an integer"}), 400
     tag_id_raw = request.args.get("tag_id")
     tag_id = int(tag_id_raw) if tag_id_raw else None
+    post_id_raw = request.args.get("post_id")
+    post_id = int(post_id_raw) if post_id_raw else None
+    artist_id_raw = request.args.get("artist_id")
+    artist_id = int(artist_id_raw) if artist_id_raw else None
 
     async with get_session() as session:
         svc = GalleryService(session)
         try:
-            page = await svc.scroll(cursor=cursor, limit=limit, tag_id=tag_id)
+            page = await svc.scroll(
+                cursor=cursor, limit=limit, tag_id=tag_id,
+                post_id=post_id, artist_id=artist_id,
+            )
         except ValueError as exc:
             return jsonify({"error": str(exc)}), 400
 
@@ -51,10 +58,21 @@ async def scroll():
 async def timeline():
     tag_id_raw = request.args.get("tag_id")
     tag_id = int(tag_id_raw) if tag_id_raw else None
+    post_id_raw = request.args.get("post_id")
+    post_id = int(post_id_raw) if post_id_raw else None
+    artist_id_raw = request.args.get("artist_id")
+    artist_id = int(artist_id_raw) if artist_id_raw else None
     async with get_session() as session:
         svc = GalleryService(session)
-        buckets = await svc.timeline(tag_id=tag_id)
-    return jsonify([{"year": b.year, "month": b.month, "count": b.count} for b in buckets])
+        try:
+            buckets = await svc.timeline(
+                tag_id=tag_id, post_id=post_id, artist_id=artist_id
+            )
+        except ValueError as exc:
+            return jsonify({"error": str(exc)}), 400
+    return jsonify(
+        [{"year": b.year, "month": b.month, "count": b.count} for b in buckets]
+    )
 
 
 @gallery_bp.route("/jump", methods=["GET"])
@@ -66,9 +84,19 @@ async def jump():
         return jsonify({"error": "year and month query params required"}), 400
     tag_id_raw = request.args.get("tag_id")
     tag_id = int(tag_id_raw) if tag_id_raw else None
+    post_id_raw = request.args.get("post_id")
+    post_id = int(post_id_raw) if post_id_raw else None
+    artist_id_raw = request.args.get("artist_id")
+    artist_id = int(artist_id_raw) if artist_id_raw else None
     async with get_session() as session:
         svc = GalleryService(session)
-        cursor = await svc.jump_cursor(year=year, month=month, tag_id=tag_id)
+        try:
+            cursor = await svc.jump_cursor(
+                year=year, month=month, tag_id=tag_id,
+                post_id=post_id, artist_id=artist_id,
+            )
+        except ValueError as exc:
+            return jsonify({"error": str(exc)}), 400
     return jsonify({"cursor": cursor})