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/adapters/arma3/remote_admin.py

@@ -0,0 +1,135 @@
+"""
+Arma3RemoteAdmin — implements the RemoteAdmin protocol using BERConClient.
+"""
+from __future__ import annotations
+
+import logging
+
+from adapters.arma3.rcon_client import BERConClient
+from adapters.exceptions import RemoteAdminError
+
+logger = logging.getLogger(__name__)
+
+
+class Arma3RemoteAdmin:
+    """
+    RemoteAdmin protocol implementation for Arma3 BattlEye RCon.
+
+    Args:
+        server_id: Database server ID.
+        host: RCon host (usually 127.0.0.1).
+        port: RCon port (usually game_port + 3).
+        password: RCon password.
+    """
+
+    def __init__(
+        self,
+        server_id: int,
+        host: str,
+        port: int,
+        password: str,
+    ) -> None:
+        self._server_id = server_id
+        self._client = BERConClient(host=host, port=port, password=password)
+
+    # ── RemoteAdmin protocol ──
+
+    def connect(self) -> None:
+        """Connect to RCon. Raises RemoteAdminError on failure."""
+        try:
+            self._client.connect()
+        except ConnectionError as exc:
+            raise RemoteAdminError(str(exc)) from exc
+
+    def disconnect(self) -> None:
+        self._client.disconnect()
+
+    def is_connected(self) -> bool:
+        return self._client.is_connected
+
+    def get_players(self) -> list[dict]:
+        """Fetch current player list."""
+        try:
+            return self._client.get_players()
+        except Exception as exc:
+            raise RemoteAdminError(f"get_players failed: {exc}") from exc
+
+    def send_command(self, command: str, timeout: float = 5.0) -> str | None:
+        """Send an arbitrary RCon command."""
+        try:
+            return self._client.send_command(command)
+        except Exception as exc:
+            raise RemoteAdminError(f"send_command failed: {exc}") from exc
+
+    def kick_player(self, player_number: int, reason: str = "") -> bool:
+        """Kick a player by their in-game slot number."""
+        command = f"kick {player_number}"
+        if reason:
+            command += f" {reason}"
+        try:
+            self._client.send_command(command)
+            return True
+        except Exception as exc:
+            logger.warning("[%s] kick_player failed for player %d: %s", self._server_id, player_number, exc)
+            return False
+
+    def ban_player(self, player_uid: str, duration_minutes: int = 0, reason: str = "") -> bool:
+        """Add a GUID ban. duration_minutes=0 means permanent."""
+        duration = duration_minutes if duration_minutes > 0 else 0
+        command = f"addBan {player_uid} {duration} {reason}"
+        try:
+            self._client.send_command(command)
+            return True
+        except Exception as exc:
+            logger.warning("[%s] ban_player failed: %s", self._server_id, exc)
+            return False
+
+    def say_all(self, message: str) -> bool:
+        """Broadcast a message to all players."""
+        try:
+            self._client.send_command(f"say -1 {message}")
+            return True
+        except Exception as exc:
+            logger.warning("[%s] say_all failed: %s", self._server_id, exc)
+            return False
+
+    def shutdown(self) -> bool:
+        """Shutdown the game server via RCon."""
+        try:
+            self._client.send_command("#shutdown")
+            return True
+        except Exception as exc:
+            logger.warning("[%s] shutdown failed: %s", self._server_id, exc)
+            return False
+
+    def keepalive(self) -> None:
+        """Send keepalive if idle."""
+        self._client.keepalive()
+
+
+class Arma3RemoteAdminFactory:
+    """
+    RemoteAdmin factory for Arma3.
+    Implements the RemoteAdmin protocol (create_client, get_startup_delay, etc.).
+    """
+
+    def create_client(self, host: str, port: int, password: str) -> Arma3RemoteAdmin:
+        """Create a new Arma3RemoteAdmin client instance."""
+        return Arma3RemoteAdmin(
+            server_id=0,  # Will be set by caller
+            host=host,
+            port=port,
+            password=password,
+        )
+
+    def get_startup_delay(self) -> float:
+        """Seconds to wait after server start before connecting."""
+        return 30.0
+
+    def get_poll_interval(self) -> float:
+        """Seconds between player list polls."""
+        return 10.0
+
+    def get_player_data_schema(self):
+        """Pydantic model for players.game_data JSON."""
+        return None