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/servers/bans_router.py

@@ -0,0 +1,142 @@
+"""Ban management endpoints — create, list, and revoke bans."""
+from __future__ import annotations
+
+import logging
+from typing import Annotated
+
+from fastapi import APIRouter, Depends, HTTPException, status
+from pydantic import BaseModel, field_validator
+from sqlalchemy.engine import Connection
+
+from adapters.arma3.ban_manager import Arma3BanManager
+from core.dal.ban_repository import BanRepository
+from core.servers.service import ServerService
+from database import get_db
+from dependencies import get_current_user, require_admin
+
+logger = logging.getLogger(__name__)
+
+router = APIRouter(prefix="/servers/{server_id}/bans", tags=["bans"])
+
+
+def _ok(data):
+    return {"success": True, "data": data, "error": None}
+
+
+class CreateBanRequest(BaseModel):
+    player_uid: str
+    ban_type: str = "GUID"
+    reason: str = ""
+    duration_minutes: int = 0  # 0 = permanent
+
+    @field_validator("ban_type")
+    @classmethod
+    def validate_ban_type(cls, v: str) -> str:
+        if v not in ("GUID", "IP"):
+            raise ValueError("ban_type must be 'GUID' or 'IP'")
+        return v
+
+    @field_validator("duration_minutes")
+    @classmethod
+    def validate_duration(cls, v: int) -> int:
+        if v < 0:
+            raise ValueError("duration_minutes cannot be negative")
+        return v
+
+
+@router.get("")
+def list_bans(
+    server_id: int,
+    db: Annotated[Connection, Depends(get_db)],
+    _user: Annotated[dict, Depends(get_current_user)],
+) -> dict:
+    """List all active bans for the server."""
+    ServerService(db).get_server(server_id)  # raises 404 if not found
+    ban_repo = BanRepository(db)
+    bans = ban_repo.get_all(server_id=server_id)
+    return _ok(bans)
+
+
+@router.post("", status_code=status.HTTP_201_CREATED)
+def create_ban(
+    server_id: int,
+    body: CreateBanRequest,
+    db: Annotated[Connection, Depends(get_db)],
+    _admin: Annotated[dict, Depends(require_admin)],
+) -> dict:
+    """Create a new ban. Writes to DB and syncs to bans.txt."""
+    ServerService(db).get_server(server_id)  # raises 404 if not found
+    ban_repo = BanRepository(db)
+
+    # Calculate expires_at if duration is set
+    expires_at = None
+    if body.duration_minutes > 0:
+        from datetime import datetime, timezone, timedelta
+        expires_at = (
+            datetime.now(timezone.utc) + timedelta(minutes=body.duration_minutes)
+        ).isoformat()
+
+    ban_id = ban_repo.create(
+        server_id=server_id,
+        guid=body.player_uid if body.ban_type == "GUID" else None,
+        name=None,
+        reason=body.reason,
+        banned_by=_admin["username"],
+        expires_at=expires_at,
+        game_data={"ban_type": body.ban_type, "duration_minutes": body.duration_minutes},
+    )
+    db.commit()
+
+    ban = ban_repo.get_by_id(ban_id)
+
+    # Sync to bans.txt (non-blocking — log error but don't fail request)
+    _sync_ban_to_file(server_id, body.player_uid, body.ban_type, body.reason, body.duration_minutes)
+
+    return _ok(ban)
+
+
+@router.delete("/{ban_id}")
+def revoke_ban(
+    server_id: int,
+    ban_id: int,
+    db: Annotated[Connection, Depends(get_db)],
+    _admin: Annotated[dict, Depends(require_admin)],
+) -> dict:
+    """Revoke a ban (marks as inactive in DB, removes from bans.txt)."""
+    ServerService(db).get_server(server_id)  # raises 404 if not found
+    ban_repo = BanRepository(db)
+    ban = ban_repo.get_by_id(ban_id)
+    if ban is None or ban["server_id"] != server_id:
+        raise HTTPException(
+            status_code=status.HTTP_404_NOT_FOUND,
+            detail={"code": "NOT_FOUND", "message": "Ban not found"},
+        )
+    ban_repo.deactivate(ban_id)
+    db.commit()
+
+    # Remove from bans.txt
+    _remove_ban_from_file(server_id, ban.get("guid") or "")
+
+    return _ok({"message": f"Ban {ban_id} revoked"})
+
+
+# ── File sync helpers ──
+
+def _sync_ban_to_file(
+    server_id: int, identifier: str, ban_type: str, reason: str, duration_minutes: int
+) -> None:
+    """Write ban to bans.txt. Log error but don't fail the request."""
+    try:
+        mgr = Arma3BanManager(server_id)
+        mgr.add_ban(identifier, ban_type, reason, duration_minutes)
+    except Exception as exc:
+        logger.error("Failed to sync ban to bans.txt for server %d: %s", server_id, exc)
+
+
+def _remove_ban_from_file(server_id: int, identifier: str) -> None:
+    """Remove ban from bans.txt. Log error but don't fail the request."""
+    try:
+        mgr = Arma3BanManager(server_id)
+        mgr.remove_ban(identifier)
+    except Exception as exc:
+        logger.error("Failed to remove ban from bans.txt for server %d: %s", server_id, exc)