feat: SQLite-backed installations, REST API, admin auth and web UI

Replaces the slice-2 hardcoded installation with a full install/deploy
pipeline:

- SQLite persistence (better-sqlite3) with a single `installations`
  table and a draft -> cloning -> building -> built -> starting ->
  running/error/stopped state machine; env vars and bearer tokens are
  encrypted at rest (AES-256-GCM, key derived from MASTER_KEY).
- Build/run orchestration: git clone (+ .env.example key detection),
  `nixpacks build` as a logged subprocess, dockerode container
  run/stop with forced host/port env vars and a TCP-connect health
  check before flipping an installation to "running".
- REST API (installations CRUD, build/deploy/redeploy, logs, token
  regeneration) behind single-operator session-cookie auth with a
  basic login lockout.
- Vite+React admin SPA: login, installation list, install wizard, and
  a detail page to configure env vars, trigger build/deploy/redeploy,
  view the build log, and copy the authenticated /mcp/<slug> URL.
- Dockerfile (multi-stage, pulls in nixpacks + the Docker CLI) and
  docker-compose.yml for production deployment.

Validated end-to-end against a real cloned repo: draft creation with
env-key detection, build, the error path on a failed health check, and
delete, all through the live API.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

apps/web/vite.config.ts

@@ -0,0 +1,11 @@
+import { defineConfig } from "vite";
+import react from "@vitejs/plugin-react";
+
+export default defineConfig({
+  plugins: [react()],
+  server: {
+    proxy: {
+      "/api": "http://localhost:3000",
+    },
+  },
+});