fix: Docker hardening, security, and deployment readiness for V1 (#82)

Phase 1 — Docker Artifact Optimization:
- Replace broad `COPY . .` with targeted frontend source copies (API/Python
  changes no longer bust the frontend build cache)
- Replace build-essential with gcc/g++ (leaner runtime)
- Fix LOG_LEVEL=debug → info for production
- Harden .dockerignore (exclude worktrees, IDE, CI, test artifacts)

Phase 2 — State & Persistence:
- Add PUID/PGID support in entrypoint.sh for bind mount compatibility
- Guard against PUID=0/PGID=0 to prevent accidental root execution
- Evict conflicting system users (e.g. node:1000) before UID remap

Phase 3 — Security:
- Always register @fastify/rate-limit so login brute-force protection
  works even when global rate limit is disabled (RATE_LIMIT_PER_MIN=0)
- Add trustProxy support (TRUST_PROXY env var, default true) so rate
  limiting and audit logs use real client IPs behind reverse proxies
- Strip stack traces from 500 error responses in production
- Fix FSTDEP022 deprecation: maxParamLength → routerOptions
- Add multi-file guard on single-file tool endpoint with clear error
  message pointing to the /batch endpoint

Phase 4 — Graceful Degradation:
- Add consolidated hardware detection startup banner (GPU, rate limit,
  upload limit, proxy status)
- Add ConnectionMonitor component with health polling and reconnecting
  overlay that auto-dismisses when the server comes back

Phase 5 — Deployment Docs:
- Rewrite deployment.md with copy-paste CPU and GPU compose templates
- Add hardware requirements table (minimum, recommended, heavy workloads)
- Add PUID/PGID bind mount documentation
- Add complete env var reference table
- Add reverse proxy guides for Nginx, Nginx Proxy Manager, Traefik,
  and Cloudflare Tunnels

docker/.dockerignore

@@ -1,14 +1,44 @@
 node_modules
 .git
+.gitignore
 .turbo
+.worktrees
 dist
 *.db
 *.db-journal
 *.db-wal
+*.db-shm
 .env
-.env.local
+.env.*
+!.env.example
 .DS_Store
 .playwright-mcp
-*.png
-*.jpg
-*.jpeg
+.mcp.json
+.superpowers
+docs/superpowers
+
+# Test artifacts
+test-results
+playwright-report
+blob-report
+tests
+coverage
+*.tsbuildinfo
+MASTER_TEST_MATRIX.md
+
+# IDE and editor files
+.vscode
+.idea
+*.swp
+*.swo
+
+# CI/release files not needed in image
+.github
+.husky
+.releaserc.json
+scripts
+
+# Large test images (favicons/logos in apps/web/public are fine)
+test-*.png
+*.heic
+*.heif