feat(ST-901): add user.active_product_id with FK to Product

- Nullable relation User → Product with onDelete: SetNull
- Index on active_product_id for join performance
- Migration: 20260427165329_add_user_active_product_id
- Install @tanstack/react-table (was missing from node_modules)
- Fix PRIORITY_COLORS ref removed in earlier refactor
- Note: User schema change affects vendor/scrum4me-mcp submodule — run prisma generate + tsc --noEmit there after merge

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

package.json

@@ -3,8 +3,8 @@
   "version": "0.3.1",
   "private": true,
   "scripts": {
-    "predev": "lsof -ti:3000 | xargs kill -9 2>/dev/null || true",
-    "dev": "concurrently \"next dev -p 3000\" \"npm run db:erd:watch\"",
+    "predev": "npx --yes kill-port 3000 || exit 0",
+    "dev": "next dev -p 3000",
     "build": "next build",
     "start": "next start",
     "lint": "eslint",