feat: bag tracking with weight distribution, packing UX overhaul — closes #13

- Bag tracking: optional admin setting under Packing addon, weight per item,
  bag assignment with inline creation, iOS-style weight sidebar + mobile modal
- Admin: merged Categories + Packing Templates into "Configuration" tab
- Packing UI: category-first workflow, mobile-friendly action buttons,
  stable category ordering, responsive button labels

server/src/db/migrations.ts

@@ -251,6 +251,19 @@ function runMigrations(db: Database.Database): void {
         sort_order INTEGER NOT NULL DEFAULT 0
       )`);
     },
+    () => {
+      db.exec(`CREATE TABLE IF NOT EXISTS packing_bags (
+        id INTEGER PRIMARY KEY AUTOINCREMENT,
+        trip_id INTEGER NOT NULL REFERENCES trips(id) ON DELETE CASCADE,
+        name TEXT NOT NULL,
+        color TEXT NOT NULL DEFAULT '#6366f1',
+        weight_limit_grams INTEGER,
+        sort_order INTEGER DEFAULT 0,
+        created_at DATETIME DEFAULT CURRENT_TIMESTAMP
+      )`);
+      try { db.exec('ALTER TABLE packing_items ADD COLUMN weight_grams INTEGER'); } catch {}
+      try { db.exec('ALTER TABLE packing_items ADD COLUMN bag_id INTEGER REFERENCES packing_bags(id) ON DELETE SET NULL'); } catch {}
+    },
   ];
 
   if (currentVersion < migrations.length) {

server/src/routes/admin.ts

@@ -266,6 +266,19 @@ router.delete('/invites/:id', (_req: Request, res: Response) => {
   res.json({ success: true });
 });
 
+// ── Bag Tracking Setting ────────────────────────────────────────────────────
+
+router.get('/bag-tracking', (_req: Request, res: Response) => {
+  const row = db.prepare("SELECT value FROM app_settings WHERE key = 'bag_tracking_enabled'").get() as { value: string } | undefined;
+  res.json({ enabled: row?.value === 'true' });
+});
+
+router.put('/bag-tracking', (req: Request, res: Response) => {
+  const { enabled } = req.body;
+  db.prepare("INSERT OR REPLACE INTO app_settings (key, value) VALUES ('bag_tracking_enabled', ?)").run(enabled ? 'true' : 'false');
+  res.json({ enabled: !!enabled });
+});
+
 // ── Packing Templates ───────────────────────────────────────────────────────
 
 router.get('/packing-templates', (_req: Request, res: Response) => {

server/src/routes/packing.ts

@@ -49,7 +49,7 @@ router.post('/', authenticate, (req: Request, res: Response) => {
 router.put('/:id', authenticate, (req: Request, res: Response) => {
   const authReq = req as AuthRequest;
   const { tripId, id } = req.params;
-  const { name, checked, category } = req.body;
+  const { name, checked, category, weight_grams, bag_id } = req.body;
 
   const trip = verifyTripOwnership(tripId, authReq.user.id);
   if (!trip) return res.status(404).json({ error: 'Trip not found' });
@@ -61,13 +61,19 @@ router.put('/:id', authenticate, (req: Request, res: Response) => {
     UPDATE packing_items SET
       name = COALESCE(?, name),
       checked = CASE WHEN ? IS NOT NULL THEN ? ELSE checked END,
-      category = COALESCE(?, category)
+      category = COALESCE(?, category),
+      weight_grams = CASE WHEN ? THEN ? ELSE weight_grams END,
+      bag_id = CASE WHEN ? THEN ? ELSE bag_id END
     WHERE id = ?
   `).run(
     name || null,
     checked !== undefined ? 1 : null,
     checked ? 1 : 0,
     category || null,
+    'weight_grams' in req.body ? 1 : 0,
+    weight_grams ?? null,
+    'bag_id' in req.body ? 1 : 0,
+    bag_id ?? null,
     id
   );
 
@@ -91,6 +97,57 @@ router.delete('/:id', authenticate, (req: Request, res: Response) => {
   broadcast(tripId, 'packing:deleted', { itemId: Number(id) }, req.headers['x-socket-id'] as string);
 });
 
+// ── Bags CRUD ───────────────────────────────────────────────────────────────
+
+router.get('/bags', authenticate, (req: Request, res: Response) => {
+  const authReq = req as AuthRequest;
+  const { tripId } = req.params;
+  const trip = verifyTripOwnership(tripId, authReq.user.id);
+  if (!trip) return res.status(404).json({ error: 'Trip not found' });
+  const bags = db.prepare('SELECT * FROM packing_bags WHERE trip_id = ? ORDER BY sort_order, id').all(tripId);
+  res.json({ bags });
+});
+
+router.post('/bags', authenticate, (req: Request, res: Response) => {
+  const authReq = req as AuthRequest;
+  const { tripId } = req.params;
+  const { name, color } = req.body;
+  const trip = verifyTripOwnership(tripId, authReq.user.id);
+  if (!trip) return res.status(404).json({ error: 'Trip not found' });
+  if (!name?.trim()) return res.status(400).json({ error: 'Name is required' });
+  const maxOrder = db.prepare('SELECT MAX(sort_order) as max FROM packing_bags WHERE trip_id = ?').get(tripId) as { max: number | null };
+  const result = db.prepare('INSERT INTO packing_bags (trip_id, name, color, sort_order) VALUES (?, ?, ?, ?)').run(tripId, name.trim(), color || '#6366f1', (maxOrder.max ?? -1) + 1);
+  const bag = db.prepare('SELECT * FROM packing_bags WHERE id = ?').get(result.lastInsertRowid);
+  res.status(201).json({ bag });
+  broadcast(tripId, 'packing:bag-created', { bag }, req.headers['x-socket-id'] as string);
+});
+
+router.put('/bags/:bagId', authenticate, (req: Request, res: Response) => {
+  const authReq = req as AuthRequest;
+  const { tripId, bagId } = req.params;
+  const { name, color, weight_limit_grams } = req.body;
+  const trip = verifyTripOwnership(tripId, authReq.user.id);
+  if (!trip) return res.status(404).json({ error: 'Trip not found' });
+  const bag = db.prepare('SELECT * FROM packing_bags WHERE id = ? AND trip_id = ?').get(bagId, tripId);
+  if (!bag) return res.status(404).json({ error: 'Bag not found' });
+  db.prepare('UPDATE packing_bags SET name = COALESCE(?, name), color = COALESCE(?, color), weight_limit_grams = ? WHERE id = ?').run(name?.trim() || null, color || null, weight_limit_grams ?? null, bagId);
+  const updated = db.prepare('SELECT * FROM packing_bags WHERE id = ?').get(bagId);
+  res.json({ bag: updated });
+  broadcast(tripId, 'packing:bag-updated', { bag: updated }, req.headers['x-socket-id'] as string);
+});
+
+router.delete('/bags/:bagId', authenticate, (req: Request, res: Response) => {
+  const authReq = req as AuthRequest;
+  const { tripId, bagId } = req.params;
+  const trip = verifyTripOwnership(tripId, authReq.user.id);
+  if (!trip) return res.status(404).json({ error: 'Trip not found' });
+  const bag = db.prepare('SELECT * FROM packing_bags WHERE id = ? AND trip_id = ?').get(bagId, tripId);
+  if (!bag) return res.status(404).json({ error: 'Bag not found' });
+  db.prepare('DELETE FROM packing_bags WHERE id = ?').run(bagId);
+  res.json({ success: true });
+  broadcast(tripId, 'packing:bag-deleted', { bagId: Number(bagId) }, req.headers['x-socket-id'] as string);
+});
+
 // ── Apply template ──────────────────────────────────────────────────────────
 
 router.post('/apply-template/:templateId', authenticate, (req: Request, res: Response) => {