feat: Phase 1 scaffold — frontend canvas + backend skeleton

Frontend:
- Vite + React 18 + TypeScript + Tailwind v4 + Shadcn/ui
- React Flow v12 canvas with all 11 node types and 5 edge types
- Dark theme with project design system (cyan, green, orange, purple accents)
- Collapsible sidebar, toolbar, detail panel
- Zustand store for canvas state
- Demo data with 10 nodes and 10 edges

Backend:
- FastAPI + SQLAlchemy async + SQLite (Python 3.13)
- DB models: Node, Edge, CanvasState, PendingDevice, ScanRun
- REST API routes: auth, nodes, edges, canvas, scan, status (WebSocket)
- JWT auth + bcrypt via config.yml
- Pydantic v2 schemas

Infra:
- GitHub Actions quality + security workflows
- .gitignore, .env.example, verify-tooling.sh, security-check.sh

.gitignore

@@ -0,0 +1,50 @@
+# Claude / project meta — never commit
+CLAUDE.md
+FEATURES.md
+.claude/
+_project_specs/
+
+# Environment files - NEVER commit
+.env
+.env.*
+!.env.example
+
+# Secrets
+*.pem
+*.key
+*.p12
+credentials.json
+secrets.json
+service-account*.json
+
+# Dependencies
+node_modules/
+__pycache__/
+*.pyc
+.venv/
+venv/
+
+# Build outputs
+dist/
+build/
+
+# IDE
+.idea/
+.vscode/settings.json
+.DS_Store
+
+# Python
+*.egg-info/
+.pytest_cache/
+.mypy_cache/
+.ruff_cache/
+htmlcov/
+.coverage
+
+# SQLite
+*.db
+*.db-shm
+*.db-wal
+
+# Docker
+.docker/