fix: remove "type" field from package.json + improve setup.sh

- Remove "type": "commonjs" from package.json — fixes Turbopack
  ESM/CommonJS conflict causing white screen in dev mode
- setup.sh: auto-generate passwords (PostgreSQL, MinIO, auth secret)
- setup.sh: auto-install Docker/Node.js if missing (apt/nvm/brew)
- setup.sh: backup existing .env before overwrite
- setup.sh: create MinIO bucket via curl if mc not installed
- setup.sh: add timeout errors for service readiness checks
- setup.sh: include pgbouncer in local dev docker compose up

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

package.json

@@ -15,7 +15,6 @@
   "keywords": [],
   "author": "",
   "license": "ISC",
-  "type": "commonjs",
   "dependencies": {
     "@livekit/components-react": "^2.9.20",
     "@livekit/components-styles": "^1.2.0",