Scaffold backend: Hono + Rivet Kit + per-user Docker stack

Backend that provisions per-user OpenCode + Gitea Docker pair via
dockerode and exposes the Grow Agent / sub-agent Rivet Kit actors
described in the PRD. Sub-agent workflows route through the parent
Grow Agent's OpenCode Docker.

- src/docker/manager.ts spawns growqr-gitea-<userId> and growqr-opencode-<userId>
- src/actors/{grow-agent,sub-agent,registry}.ts: Rivet Kit actors
- src/routes/{actors,opencode,git}.ts: PRD section 5.2-5.4 HTTP API
- docker-compose.yml runs rivet-engine + backend (mounts host Docker socket)
- PRD updated to lock in per-user OpenCode/Gitea Docker topology

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

tsconfig.json

@@ -0,0 +1,21 @@
+{
+  "compilerOptions": {
+    "target": "ES2022",
+    "module": "ES2022",
+    "moduleResolution": "Bundler",
+    "lib": ["ES2022"],
+    "outDir": "dist",
+    "rootDir": "src",
+    "strict": true,
+    "esModuleInterop": true,
+    "skipLibCheck": true,
+    "forceConsistentCasingInFileNames": true,
+    "resolveJsonModule": true,
+    "declaration": false,
+    "sourceMap": true,
+    "noUncheckedIndexedAccess": true,
+    "types": ["node"]
+  },
+  "include": ["src/**/*"],
+  "exclude": ["node_modules", "dist", "growqr-frontend"]
+}