feat: initial scaffold - backend, frontend, Prisma schema, Docker

- Prisma schema: User, Session, RepoConfig, Preview, Job, WebhookToken, NoConfigComment, AdminSettings
- Backend: auth (login/logout/me/first-user setup), webhook handler with HMAC verification, EC2 service, SSH service, deploy pipeline, job queue worker, cron workers
- Frontend: Login with first-user detection, Dashboard, PreviewDetail with live log streaming, Settings, Repos config, Admin panel, SetupWizard, Privacy page
- Docker Compose and Dockerfile for self-hosted deployment
- Uses bcryptjs for Node 24 compatibility

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

package.json

@@ -0,0 +1,8 @@
+{
+  "devDependencies": {
+    "prisma": "^6.19.3"
+  },
+  "dependencies": {
+    "@prisma/client": "^6.19.3"
+  }
+}