feat: initial WireGUI implementation — full VPN management platform

Complete Python/NiceGUI rewrite of the Wirezone (Elixir/Phoenix) VPN
management platform. All 10 implementation phases delivered.

Core stack:
- NiceGUI reactive UI with SQLModel ORM on PostgreSQL (asyncpg)
- Alembic migrations, Valkey/Redis cache, pydantic-settings config
- WireGuard management via subprocess (wg/ip/nft CLIs)
- 164 tests passing, 35% code coverage

Features:
- User/device/rule CRUD with admin and unprivileged roles
- Full device config form with per-device WG overrides
- WireGuard client config generation with QR codes
- REST API (v0) with Bearer token auth for all resources
- TOTP MFA with QR registration and challenge flow
- OIDC SSO with authlib (provider registry, auto-create users)
- Magic link passwordless sign-in via email
- SAML SP-initiated SSO with IdP metadata parsing
- WebAuthn/FIDO2 security key registration
- nftables firewall with per-user chains and masquerade
- Background tasks: WG stats polling, VPN session expiry,
  OIDC token refresh, WAN connectivity checks
- Startup reconciliation (DB ↔ WireGuard state sync)
- In-memory notification system with header badge
- Admin UI: users, devices, rules, settings (3 tabs), diagnostics
- Loguru logging with optional timestamped file output

Deployment:
- Multi-stage Dockerfile (python:3.13-slim)
- Docker Compose prod stack (bridge networking, NET_ADMIN, nftables)
- Forgejo CI: tests → semantic versioning → Docker registry push
- Health endpoint at /api/health

.dockerignore

@@ -0,0 +1,13 @@
+.venv/
+__pycache__/
+*.pyc
+.env
+.nicegui/
+logs/
+.git/
+.idea/
+.pytest_cache/
+tests/
+.forgejo/
+*.md
+compose*.yml