Add bbox coordinates to object_pictures for chip highlight feature

- Add bbox_x/y/w/h FLOAT columns to object_pictures (0–1 percentage range)
- Include type ('word'|'object') and bbox in feed placeholder response
- Fix picture query to use DISTINCT ON instead of LIMIT 1

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/routes/feed.js

@@ -94,7 +94,9 @@ router.get('/', requireJwt, async (req, res, next) => {
         `SELECT id, titel_de AS de, titel_en AS en, titel_sv AS sv FROM words WHERE id = ANY($1)`,
         [uuidArr]
       );
-      wordRes.rows.forEach(w => { placeholderMap[w.id] = { de: w.de, en: w.en, sv: w.sv }; });
+      wordRes.rows.forEach(w => {
+        placeholderMap[w.id] = { de: w.de, en: w.en, sv: w.sv, type: 'word', bbox: null };
+      });
 
       // Object lookup → get first linked word as label
       const objUuids = uuidArr.filter(u => !placeholderMap[u]);
@@ -109,7 +111,10 @@ router.get('/', requireJwt, async (req, res, next) => {
         // First word per object
         const seen = new Set();
         objRes.rows.forEach(r => {
-          if (!seen.has(r.id)) { placeholderMap[r.id] = { de: r.de, en: r.en, sv: r.sv }; seen.add(r.id); }
+          if (!seen.has(r.id)) {
+            placeholderMap[r.id] = { de: r.de, en: r.en, sv: r.sv, type: 'object', bbox: null };
+            seen.add(r.id);
+          }
         });
       }
     }
@@ -156,14 +161,24 @@ router.get('/', requireJwt, async (req, res, next) => {
     const pictureMap = {}; // objectId → { url, blurhash }
     if (resolvedObjectIds.size) {
       const picRes = await query(
-        `SELECT op.object_id, p.picture_link AS url, p.blurhash
+        `SELECT DISTINCT ON (op.object_id)
+                op.object_id, p.picture_link AS url, p.blurhash,
+                op.bbox_x, op.bbox_y, op.bbox_w, op.bbox_h
            FROM object_pictures op
            JOIN pictures p ON p.id = op.picture_id
           WHERE op.object_id = ANY($1)
-          LIMIT 1`,
+          ORDER BY op.object_id, p.created_at`,
         [[...resolvedObjectIds]]
       );
-      picRes.rows.forEach(r => { pictureMap[r.object_id] = { url: r.url, blurhash: r.blurhash }; });
+      picRes.rows.forEach(r => {
+        pictureMap[r.object_id] = { url: r.url, blurhash: r.blurhash };
+        // Attach bbox to placeholder if all four values are present
+        if (placeholderMap[r.object_id] && r.bbox_x != null) {
+          placeholderMap[r.object_id].bbox = {
+            x: r.bbox_x, y: r.bbox_y, w: r.bbox_w, h: r.bbox_h,
+          };
+        }
+      });
     }
 
     // Pick first available picture across all placeholders in the pair