fix: require master password for admin and wipe-device actions

Gate invite management, user ban/delete, and delete-all-devices behind
masterPasswordHash verification, matching backup step-up auth. The web UI
prompts for the master password in the shared confirm dialog.

src/handlers/devices.ts

@@ -464,11 +464,26 @@ export async function handleUpdateDeviceName(
 
 // DELETE /api/devices
 export async function handleDeleteAllDevices(request: Request, env: Env, userId: string): Promise<Response> {
-  void request;
   const storage = new StorageService(env.DB);
   const user = await storage.getUserById(userId);
   if (!user) return errorResponse('User not found', 404);
 
+  let masterPasswordHash = '';
+  try {
+    const body = await request.json() as { masterPasswordHash?: string };
+    masterPasswordHash = String(body?.masterPasswordHash || '').trim();
+  } catch {
+    masterPasswordHash = '';
+  }
+  if (!masterPasswordHash) {
+    return errorResponse('masterPasswordHash is required', 400);
+  }
+  const auth = new AuthService(env);
+  const passwordValid = await auth.verifyPassword(masterPasswordHash, user.masterPasswordHash, user.email);
+  if (!passwordValid) {
+    return errorResponse('Invalid password', 400);
+  }
+
   const [removedTrusted, removedSessions, removedDevices] = await Promise.all([
     storage.deleteTrustedTwoFactorTokensByUserId(userId),
     storage.deleteRefreshTokensByUserId(userId),