feat: Stage 2 — authentication and setup flow

Backend (tasks 2.1–2.6, 2.10):
- settings_repo: get/set/delete/get_all CRUD for the key-value settings table
- session_repo: create/get/delete/delete_expired for session rows
- setup_service: bcrypt password hashing, one-time-only enforcement,
  run_setup() / is_setup_complete() / get_password_hash()
- auth_service: login() with bcrypt verify + token creation,
  validate_session() with expiry check, logout()
- setup router: GET /api/setup (status), POST /api/setup (201 / 409)
- auth router: POST /api/auth/login (token + HttpOnly cookie),
               POST /api/auth/logout (clears cookie, idempotent)
- SetupRedirectMiddleware: 307 → /api/setup for all API paths until setup done
- require_auth dependency: cookie or Bearer token → Session or 401
- conftest.py: manually bootstraps app.state.db for router tests
  (ASGITransport does not trigger ASGI lifespan)
- 85 tests pass; ruff 0 errors; mypy --strict 0 errors

Frontend (tasks 2.7–2.9):
- types/auth.ts, types/setup.ts, api/auth.ts, api/setup.ts
- AuthProvider: sessionStorage-backed context (isAuthenticated, login, logout)
- RequireAuth: guard component → /login?next=<path> when unauthenticated
- SetupPage: Fluent UI form, client-side validation, inline errors
- LoginPage: single password input, ?next= redirect after success
- DashboardPage: placeholder (full impl Stage 5)
- App.tsx: full route tree (/setup, /login, /, *)

backend/tests/test_routers/test_setup.py

@@ -0,0 +1,123 @@
+"""Tests for the setup router (POST /api/setup, GET /api/setup)."""
+
+from __future__ import annotations
+
+from httpx import AsyncClient
+
+
+class TestGetSetupStatus:
+    """GET /api/setup — check setup completion state."""
+
+    async def test_returns_not_completed_on_fresh_db(self, client: AsyncClient) -> None:
+        """Status endpoint reports setup not done on a fresh database."""
+        response = await client.get("/api/setup")
+        assert response.status_code == 200
+        assert response.json() == {"completed": False}
+
+    async def test_returns_completed_after_setup(self, client: AsyncClient) -> None:
+        """Status endpoint reports setup done after POST /api/setup."""
+        await client.post(
+            "/api/setup",
+            json={
+                "master_password": "supersecret123",
+                "database_path": "bangui.db",
+                "fail2ban_socket": "/var/run/fail2ban/fail2ban.sock",
+                "timezone": "UTC",
+                "session_duration_minutes": 60,
+            },
+        )
+        response = await client.get("/api/setup")
+        assert response.status_code == 200
+        assert response.json() == {"completed": True}
+
+
+class TestPostSetup:
+    """POST /api/setup — run the first-run configuration wizard."""
+
+    async def test_accepts_valid_payload(self, client: AsyncClient) -> None:
+        """Setup endpoint returns 201 for a valid first-run payload."""
+        response = await client.post(
+            "/api/setup",
+            json={
+                "master_password": "supersecret123",
+                "database_path": "bangui.db",
+                "fail2ban_socket": "/var/run/fail2ban/fail2ban.sock",
+                "timezone": "UTC",
+                "session_duration_minutes": 60,
+            },
+        )
+        assert response.status_code == 201
+        body = response.json()
+        assert "message" in body
+
+    async def test_rejects_short_password(self, client: AsyncClient) -> None:
+        """Setup endpoint rejects passwords shorter than 8 characters."""
+        response = await client.post(
+            "/api/setup",
+            json={"master_password": "short"},
+        )
+        assert response.status_code == 422
+
+    async def test_rejects_second_call(self, client: AsyncClient) -> None:
+        """Setup endpoint returns 409 if setup has already been completed."""
+        payload = {
+            "master_password": "supersecret123",
+            "database_path": "bangui.db",
+            "fail2ban_socket": "/var/run/fail2ban/fail2ban.sock",
+            "timezone": "UTC",
+            "session_duration_minutes": 60,
+        }
+        first = await client.post("/api/setup", json=payload)
+        assert first.status_code == 201
+
+        second = await client.post("/api/setup", json=payload)
+        assert second.status_code == 409
+
+    async def test_accepts_defaults_for_optional_fields(
+        self, client: AsyncClient
+    ) -> None:
+        """Setup endpoint uses defaults when optional fields are omitted."""
+        response = await client.post(
+            "/api/setup",
+            json={"master_password": "supersecret123"},
+        )
+        assert response.status_code == 201
+
+
+class TestSetupRedirectMiddleware:
+    """Verify that the setup-redirect middleware enforces setup-first."""
+
+    async def test_protected_endpoint_redirects_before_setup(
+        self, client: AsyncClient
+    ) -> None:
+        """Non-setup API requests redirect to /api/setup on a fresh instance."""
+        response = await client.get(
+            "/api/auth/login",
+            follow_redirects=False,
+        )
+        # Middleware issues 307 redirect to /api/setup
+        assert response.status_code == 307
+        assert response.headers["location"] == "/api/setup"
+
+    async def test_health_always_reachable_before_setup(
+        self, client: AsyncClient
+    ) -> None:
+        """Health endpoint is always reachable even before setup."""
+        response = await client.get("/api/health")
+        assert response.status_code == 200
+
+    async def test_no_redirect_after_setup(self, client: AsyncClient) -> None:
+        """Protected endpoints are reachable (no redirect) after setup."""
+        await client.post(
+            "/api/setup",
+            json={"master_password": "supersecret123"},
+        )
+        # /api/auth/login should now be reachable (returns 405 GET not allowed,
+        # not a setup redirect)
+        response = await client.post(
+            "/api/auth/login",
+            json={"password": "wrong"},
+            follow_redirects=False,
+        )
+        # 401 wrong password — not a 307 redirect
+        assert response.status_code == 401