feat: Windows admin in Settings UI and WinRM host test (0.10.1)

Store domain admin in ui_settings (DB overrides env); qwinsta/logoff use effective config.
Host card: POST /hosts/{id}/actions/winrm-test via pywinrm.

backend/app/api/v1/settings.py

@@ -37,6 +37,17 @@ from app.services.ui_settings import (
     get_effective_ui_settings,
     upsert_ui_settings,
 )
+from app.services.win_admin_settings import (
+    get_effective_win_admin_config,
+    upsert_win_admin_settings,
+)
+from app.services.winrm_connect import (
+    HostNotWindowsError,
+    HostTargetMissingError,
+    WinAdminNotConfiguredError,
+    resolve_windows_host_target,
+    test_winrm_connection,
+)
 
 router = APIRouter(prefix="/settings", tags=["settings"])
 
@@ -439,3 +450,46 @@ def update_ui_settings(
         show_sidebar_system_stats=cfg.show_sidebar_system_stats,
         source=cfg.source,
     )
+
+
+class WinAdminSettingsResponse(BaseModel):
+    configured: bool
+    user: str | None = None
+    password_hint: str | None = None
+    source: str = Field(description="env или db")
+
+
+class WinAdminSettingsUpdate(BaseModel):
+    user: str | None = None
+    password: str | None = None
+
+
+@router.get("/win-admin", response_model=WinAdminSettingsResponse)
+def get_win_admin_settings(
+    db: Session = Depends(get_db),
+    _user=Depends(require_admin),
+) -> WinAdminSettingsResponse:
+    cfg = get_effective_win_admin_config(db)
+    return WinAdminSettingsResponse(
+        configured=cfg.configured,
+        user=cfg.user or None,
+        password_hint=_mask_secret(cfg.password),
+        source=cfg.source,
+    )
+
+
+@router.put("/win-admin", response_model=WinAdminSettingsResponse)
+def update_win_admin_settings(
+    body: WinAdminSettingsUpdate,
+    db: Session = Depends(get_db),
+    _user=Depends(require_admin),
+) -> WinAdminSettingsResponse:
+    if body.user is not None and not body.user.strip():
+        raise HTTPException(status_code=422, detail="user must not be empty")
+    cfg = upsert_win_admin_settings(db, user=body.user, password=body.password)
+    return WinAdminSettingsResponse(
+        configured=cfg.configured,
+        user=cfg.user or None,
+        password_hint=_mask_secret(cfg.password),
+        source=cfg.source,
+    )