feat: implement full backend + frontend server detail, settings, and create server pages

Backend:
- Complete FastAPI backend with 42+ REST endpoints (auth, servers, config,
  players, bans, missions, mods, games, system)
- Game adapter architecture with Arma 3 as first-class adapter
- WebSocket real-time events for status, metrics, logs, players
- Background thread system (process monitor, metrics, log tail, RCon poller)
- Fernet encryption for sensitive config fields at rest
- JWT auth with admin/viewer roles, bcrypt password hashing
- SQLite with WAL mode, parameterized queries, migration system
- APScheduler cleanup jobs for logs, metrics, events

Frontend:
- Server Detail page with 7 tabs (overview, config, players, bans,
  missions, mods, logs)
- Settings page with password change and admin user management
- Create Server wizard (4-step; known bug: silent validation failure)
- New hooks: useServerDetail, useAuth, useGames
- New components: ServerHeader, ConfigEditor, PlayerTable, BanTable,
  MissionList, ModList, LogViewer, PasswordChange, UserManager
- WebSocket onEvent callback for real-time log accumulation
- 120 unit tests passing (Vitest + React Testing Library)

Docs:
- Added .gitignore, CLAUDE.md, README.md
- Updated FRONTEND.md, ARCHITECTURE.md with current implementation state
- Added .env.example for backend configuration

Known issues:
- Create Server form: "Next" buttons don't validate before advancing,
  causing silent submit failure when fields are invalid
- Config sub-tabs need UX redesign for non-technical users

backend/core/system/router.py

@@ -0,0 +1,32 @@
+from fastapi import APIRouter, Depends
+from typing import Annotated
+from dependencies import get_current_user
+from adapters.registry import GameAdapterRegistry
+
+router = APIRouter(prefix="/system", tags=["system"])
+
+
+@router.get("/health")
+def health():
+    return {"status": "ok"}
+
+
+@router.get("/status")
+def system_status(_user: Annotated[dict, Depends(get_current_user)]):
+    from sqlalchemy import text
+    from database import get_engine
+    with get_engine().connect() as db:
+        running = db.execute(
+            text("SELECT COUNT(*) FROM servers WHERE status IN ('running','starting')")
+        ).fetchone()[0]
+        total = db.execute(text("SELECT COUNT(*) FROM servers")).fetchone()[0]
+
+    return {
+        "success": True,
+        "data": {
+            "version": "1.0.0",
+            "running_servers": running,
+            "total_servers": total,
+            "supported_games": [a.game_type for a in GameAdapterRegistry.all()],
+        },
+    }