feat: add CI/CD pipeline, production Dockerfile, and deployment architecture

- Add production Dockerfile with bun build --compile, multi-stage Alpine build
- Add .dockerignore
- Swap bcrypt -> bcryptjs (pure JS, no native addons)
- Add programmatic migrations on startup via drizzle migrator
- Add /v1/version endpoint with APP_VERSION baked in at build time
- Add .gitea/workflows/ci.yml (lint + test with postgres/valkey services)
- Add .gitea/workflows/build.yml (version bump, build, push to registry)
- Update CLAUDE.md and docs/architecture.md to remove multi-tenancy
- Add docs/deployment.md covering DOKS + ArgoCD architecture

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

packages/backend/package.json

@@ -23,7 +23,8 @@
     "@fastify/multipart": "^9.4.0",
     "@fastify/rate-limit": "^10.3.0",
     "@lunarfront/shared": "workspace:*",
-    "bcrypt": "^6",
+    "@types/bcryptjs": "^3.0.0",
+    "bcryptjs": "^3.0.3",
     "drizzle-orm": "^0.38",
     "fastify": "^5",
     "fastify-plugin": "^5",
@@ -32,10 +33,9 @@
     "zod": "^4"
   },
   "devDependencies": {
-    "typescript": "^5",
+    "@types/node": "^22",
     "drizzle-kit": "^0.30",
     "pino-pretty": "^13",
-    "@types/node": "^22",
-    "@types/bcrypt": "^5"
+    "typescript": "^5"
   }
 }