feat: Stage 1 — backend and frontend scaffolding

Backend (tasks 1.1, 1.5–1.8):
- pyproject.toml with FastAPI, Pydantic v2, aiosqlite, APScheduler 3.x,
  structlog, bcrypt; ruff + mypy strict configured
- Pydantic Settings (BANGUI_ prefix env vars, fail-fast validation)
- SQLite schema: settings, sessions, blocklist_sources, import_log;
  WAL mode + foreign keys; idempotent init_db()
- FastAPI app factory with lifespan (DB, aiohttp session, scheduler),
  CORS, unhandled-exception handler, GET /api/health
- Fail2BanClient: async Unix-socket wrapper using run_in_executor,
  custom error types, async context manager
- Utility modules: ip_utils, time_utils, constants
- 47 tests; ruff 0 errors; mypy --strict 0 errors

Frontend (tasks 1.2–1.4):
- Vite + React 18 + TypeScript strict; Fluent UI v9; ESLint + Prettier
- Custom brand theme (#0F6CBD, WCAG AA contrast) with light/dark variants
- Typed fetch API client (ApiError, get/post/put/del) + endpoints constants
- tsc --noEmit 0 errors

.gitignore

@@ -0,0 +1,34 @@
+# Python
+__pycache__/
+*.py[cod]
+*.pyo
+.coverage
+.coverage.*
+htmlcov/
+.pytest_cache/
+.mypy_cache/
+.ruff_cache/
+dist/
+build/
+*.egg-info/
+.venv/
+venv/
+env/
+
+# Node
+node_modules/
+dist/
+.vite/
+
+# Env
+.env
+*.env
+
+# OS
+.DS_Store
+Thumbs.db
+
+# Editor
+.idea/
+*.swp
+*.swo