feat: Lsky/COS gateway - attachments upload direct to object storage (remote_url/remote_thumb), preview loads from COS, graceful local fallback

app/server/db.mjs

@@ -125,7 +125,7 @@ function preMigrateColumns(d) {
     }
   };
   for (const t of SYNC_TABLES) addCols(t, SYNC_COLS);
-  addCols('attachment', [['sha256', 'TEXT'], ['thumb_rel_path', 'TEXT']]);
+  addCols('attachment', [['sha256', 'TEXT'], ['thumb_rel_path', 'TEXT'], ['remote_url', 'TEXT'], ['remote_thumb', 'TEXT']]);
 }
 
 export function migrateSync(d) {
@@ -1078,6 +1078,19 @@ function listFootprints(d, query) {
       return { data_b64: data.toString('base64'), mime: row.thumb_rel_path ? 'image/webp' : row.mime, file_name: row.file_name };
     }
 
+    case 'attachment_set_remote': {
+      // 图床（Lsky/COS）直传成功后回填远程地址；同步到所有端
+      const row = d.prepare('SELECT * FROM attachment WHERE id=?').get(payload.id);
+      if (!row) throw new Error('附件不存在');
+      withTx(d, () => {
+        const h = hlcNext(d);
+        d.prepare('UPDATE attachment SET remote_url=?, remote_thumb=?, hlc=? WHERE id=?')
+          .run(payload.remote_url ?? null, payload.remote_thumb ?? null, h, row.id);
+        touchOplog(d, 'attachment', row.uuid, 'upsert', h);
+      });
+      return { ok: true };
+    }
+
     case 'view_list':
       return { items: d.prepare('SELECT * FROM saved_view WHERE deleted_at IS NULL ORDER BY id').all().map(v => ({
         ...v, filter: JSON.parse(v.filter || '{}'), sort: JSON.parse(v.sort || '{}'), is_default: !!v.is_default