The Next.js auth middleware (proxy.ts) was never wired in — it exported
`proxy` from a file named proxy.ts, but Next.js requires a `middleware`
export from middleware.ts. The middleware-manifest.json was empty,
leaving all 42 API routes accessible without authentication.
Fixes:
- Rename web/proxy.ts → web/middleware.ts, export `middleware` not `proxy`
- Add defense-in-depth auth-guard to /api/shutdown and /api/update routes
- Remove shell: true from update-service spawn (command injection surface)
- Update contract tests to verify middleware file name and export
Closes#4014
Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
