feat(ci): add format check, PR validation, and Docker buildx

- Add cargo fmt --check to enforce code formatting
- Add pull_request trigger for PR validation
- Split workflow into parallel jobs (format, clippy, build, docker)
- Integrate Docker Buildx with DinD service
- Add BuildKit caching for faster builds
- Add local test script (scripts/test-ci-locally.sh)
- Add comprehensive documentation

All local CI checks pass ✅

docs/development/CI-QUICK-REFERENCE.md

@@ -0,0 +1,94 @@
+# CI/CD Quick Reference
+
+Fast reference for the Forgejo CI/CD pipeline.
+
+---
+
+## Trigger CI
+
+```bash
+# Push to main or develop
+git push origin main
+git push origin develop
+
+# Create/update pull request
+# Automatically triggers CI
+```
+
+---
+
+## Local Pre-Commit Check
+
+```bash
+# Run all CI checks locally
+./scripts/test-ci-locally.sh
+
+# Individual checks
+cd backend
+cargo fmt --all -- --check        # Format check
+cargo clippy --all-targets --all-features -- -D warnings  # Lint
+cargo build --release             # Build
+```
+
+---
+
+## Fix Common Issues
+
+### Format Fail
+```bash
+cd backend
+cargo fmt --all
+git commit -am "style: auto-format"
+```
+
+### Clippy Fail
+```bash
+cd backend
+cargo clippy --all-targets --all-features -- -D warnings
+# Fix issues, then commit
+```
+
+---
+
+## CI Jobs
+
+| Job | Time | Purpose |
+|-----|------|---------|
+| format | ~10s | Check code formatting |
+| clippy | ~30s | Run linter |
+| build | ~60s | Build binary |
+| docker-build | ~40s | Build Docker image |
+
+**Total**: ~2.5 min (parallel execution)
+
+---
+
+## Monitor CI
+
+URL: http://gitea.soliverez.com.ar/alvaro/normogen/actions
+
+---
+
+## Docker Build Details
+
+- **Builder**: Docker Buildx v0.29.1
+- **Service**: DinD (docker:dind)
+- **Socket**: TCP (localhost:2375)
+- **Cache**: BuildKit local cache
+- **Images**: 
+  - `normogen-backend:latest`
+  - `normogen-backend:{sha}`
+
+---
+
+## Workflow File
+
+`.forgejo/workflows/lint-and-build.yml`
+
+---
+
+## Documentation
+
+- [Full Documentation](./CI-IMPROVEMENTS.md)
+- [Implementation Summary](../CI-CD-IMPLEMENTATION-SUMMARY.md)
+- [Original Pipeline](./FORGEJO-CI-CD-PIPELINE.md)