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/registry.py

@@ -0,0 +1,66 @@
+"""
+GameAdapterRegistry — singleton that holds all registered game adapters.
+Adapters register themselves at import time.
+"""
+from __future__ import annotations
+
+import logging
+
+logger = logging.getLogger(__name__)
+
+
+class GameAdapterRegistry:
+    _adapters: dict[str, object] = {}  # game_type -> GameAdapter
+
+    @classmethod
+    def register(cls, adapter) -> None:
+        """Register a game adapter. Called at import time by each adapter package."""
+        if adapter.game_type in cls._adapters:
+            logger.warning(
+                "Adapter for '%s' already registered. Overwriting.", adapter.game_type
+            )
+        cls._adapters[adapter.game_type] = adapter
+        logger.info("Registered game adapter: %s (%s)", adapter.game_type, adapter.display_name)
+
+    @classmethod
+    def get(cls, game_type: str):
+        """
+        Get adapter by game_type. Raises KeyError if not registered.
+        Core code calls this whenever game-specific behavior is needed.
+        """
+        adapter = cls._adapters.get(game_type)
+        if adapter is None:
+            raise KeyError(
+                f"No adapter registered for game type '{game_type}'. "
+                f"Available: {list(cls._adapters.keys())}"
+            )
+        return adapter
+
+    @classmethod
+    def all(cls) -> list:
+        """Return all registered adapters."""
+        return list(cls._adapters.values())
+
+    @classmethod
+    def list_game_types(cls) -> list[dict]:
+        """Return metadata list for API /games endpoint."""
+        result = []
+        for adapter in cls._adapters.values():
+            caps = []
+            for cap in [
+                "config_generator", "process_config", "log_parser",
+                "remote_admin", "mission_manager", "mod_manager", "ban_manager",
+            ]:
+                if adapter.has_capability(cap):
+                    caps.append(cap)
+            result.append({
+                "game_type": adapter.game_type,
+                "display_name": adapter.display_name,
+                "version": adapter.version,
+                "capabilities": caps,
+            })
+        return result
+
+    @classmethod
+    def is_registered(cls, game_type: str) -> bool:
+        return game_type in cls._adapters