feat: POST /auth/workspaces — create an additional collective from an existing account

Until now collectives only existed at registration; an account with a
personal workspace had no path to start one. The creator becomes Owner
and gets a session scoped to the new workspace.

apps/media-worker/package.json

@@ -13,10 +13,13 @@
     "soak": "node --import tsx src/compositor/soak.ts"
   },
   "dependencies": {
+    "@aws-sdk/client-s3": "^3.1146.0",
+    "pg": "^8.23.1",
     "pino": "^9.3.2"
   },
   "devDependencies": {
     "@types/node": "^22.5.0",
+    "@types/pg": "^8.23.1",
     "tsx": "^4.17.0"
   }
 }