Add NixOS VM integration tests and update CI/CD pipeline configuration. Introduce checks for backend integration, full-stack, performance, and security tests using native NixOS services. Remove legacy GitHub Actions workflow and replace with Gitea Actions runner configuration. Update README and quickstart guide to reflect new development environment setup and testing commands.

specs/001-reference-board-viewer/quickstart.md

@@ -16,16 +16,17 @@ This guide will get you from zero to a running development environment for the R
 # Clone repository (if not already)
 cd /home/jawz/Development/Projects/personal/webref
 
-# Enter Nix development shell (installs all dependencies)
+# Enter Nix development shell (from flake.nix)
 nix develop
 
 # Verify tools are available
-python --version    # Should show Python 3.12+
-node --version      # Should show Node.js latest
+python --version    # Python 3.12
+node --version      # Node.js 20+
 psql --version      # PostgreSQL client
+ruff --version      # Python linter
 ```
 
-**What this does:** Nix installs all verified dependencies from nixpkgs (see VERIFICATION-COMPLETE.md)
+**What this does:** `flake.nix` provides all dependencies (Python, Node.js, PostgreSQL, MinIO, etc.)
 
 ---
 
@@ -240,26 +241,42 @@ webref/
 
 ### Backend
 ```bash
+# All commands run inside nix develop shell
+
 # Run API server
-uvicorn app.main:app --reload
+cd backend && uvicorn app.main:app --reload
 
 # Run tests
-pytest
+cd backend && pytest
 
 # Run with coverage
-pytest --cov=app --cov-report=html
+cd backend && pytest --cov=app --cov-report=html
 
 # Check linting
-ruff check app/
+cd backend && ruff check app/
 
 # Format code
-ruff format app/
+cd backend && ruff format app/
 
 # Run migrations
-alembic upgrade head
+cd backend && alembic upgrade head
 
 # Create migration
-alembic revision --autogenerate -m "description"
+cd backend && alembic revision --autogenerate -m "description"
+```
+
+### NixOS VM Integration Tests
+```bash
+# Run all tests (backend, full-stack, performance, security)
+nix flake check
+
+# Run specific test
+nix build .#checks.backend-integration -L
+nix build .#checks.full-stack -L
+
+# Interactive debugging
+nix build .#checks.backend-integration.driverInteractive
+./result/bin/nixos-test-driver
 ```
 
 ### Frontend