command-gate: restore the /start filter and remove the fail-open admin check

Add '/start' back to the host FILTERED set (a Telegram fix from 866b791
was silently undone when host gating was added) so it is dropped instead
of reaching the agent as a normal message. Replace the inline isAdmin
query and its hasTable('user_roles') fail-open guard with a call to
hasAdminPrivilege; user_roles always exists (core migration 001-initial),
so the guard only ever masked a missing check. Add a focused command-gate
test covering both.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/command-gate.test.ts

@@ -0,0 +1,83 @@
+/**
+ * Tests for the host-side command gate — filtered commands are dropped
+ * before reaching the container, and admin commands are gated against
+ * the user_roles table.
+ */
+import { afterEach, beforeEach, describe, expect, it } from 'vitest';
+
+import { gateCommand } from './command-gate.js';
+import { closeDb, createAgentGroup, initTestDb, runMigrations } from './db/index.js';
+import { createUser } from './modules/permissions/db/users.js';
+import { grantRole } from './modules/permissions/db/user-roles.js';
+
+function now(): string {
+  return new Date().toISOString();
+}
+
+function seedAgentGroup(id: string): void {
+  createAgentGroup({ id, name: id.toUpperCase(), folder: id, agent_provider: null, created_at: now() });
+}
+
+function seedUser(id: string): void {
+  createUser({ id, kind: 'telegram', display_name: null, created_at: now() });
+}
+
+beforeEach(() => {
+  const db = initTestDb();
+  runMigrations(db);
+  seedAgentGroup('ag-1');
+  seedAgentGroup('ag-2');
+});
+
+afterEach(() => {
+  closeDb();
+});
+
+describe('filtered commands', () => {
+  it('drops /start before it reaches the container', () => {
+    expect(gateCommand('/start', 'telegram:1', 'ag-1')).toEqual({ action: 'filter' });
+  });
+
+  it('drops /start regardless of sender', () => {
+    expect(gateCommand('/start', null, 'ag-1')).toEqual({ action: 'filter' });
+  });
+});
+
+describe('admin gating goes through roles', () => {
+  it('denies an admin command from a non-admin user', () => {
+    expect(gateCommand('/clear', 'telegram:nobody', 'ag-1')).toEqual({ action: 'deny', command: '/clear' });
+  });
+
+  it('denies an admin command with no sender', () => {
+    expect(gateCommand('/clear', null, 'ag-1')).toEqual({ action: 'deny', command: '/clear' });
+  });
+
+  it('allows an admin command from an owner', () => {
+    seedUser('telegram:owner');
+    grantRole({ user_id: 'telegram:owner', role: 'owner', agent_group_id: null, granted_by: null, granted_at: now() });
+    expect(gateCommand('/clear', 'telegram:owner', 'ag-1')).toEqual({ action: 'pass' });
+  });
+
+  it('allows an admin command from a scoped admin of the group', () => {
+    seedUser('telegram:admin');
+    grantRole({
+      user_id: 'telegram:admin',
+      role: 'admin',
+      agent_group_id: 'ag-1',
+      granted_by: null,
+      granted_at: now(),
+    });
+    expect(gateCommand('/clear', 'telegram:admin', 'ag-1')).toEqual({ action: 'pass' });
+    expect(gateCommand('/clear', 'telegram:admin', 'ag-2')).toEqual({ action: 'deny', command: '/clear' });
+  });
+});
+
+describe('normal messages pass through', () => {
+  it('passes a plain message', () => {
+    expect(gateCommand('hello there', 'telegram:1', 'ag-1')).toEqual({ action: 'pass' });
+  });
+
+  it('passes an unknown slash command', () => {
+    expect(gateCommand('/whatever', 'telegram:1', 'ag-1')).toEqual({ action: 'pass' });
+  });
+});

src/command-gate.ts

@@ -7,11 +7,11 @@
  *   "Permission denied" response written directly to messages_out
  * - Normal messages: pass through unchanged
  */
-import { getDb, hasTable } from './db/connection.js';
+import { hasAdminPrivilege } from './modules/permissions/db/user-roles.js';
 
 export type GateResult = { action: 'pass' } | { action: 'filter' } | { action: 'deny'; command: string };
 
-const FILTERED_COMMANDS = new Set(['/help', '/login', '/logout', '/doctor', '/config', '/remote-control']);
+const FILTERED_COMMANDS = new Set(['/start', '/help', '/login', '/logout', '/doctor', '/config', '/remote-control']);
 const ADMIN_COMMANDS = new Set(['/clear', '/compact', '/context', '/cost', '/files', '/upload-trace']);
 
 /**
@@ -48,16 +48,5 @@ export function gateCommand(content: string, userId: string | null, agentGroupId
 
 function isAdmin(userId: string | null, agentGroupId: string): boolean {
   if (!userId) return false;
-  if (!hasTable(getDb(), 'user_roles')) return true; // no permissions module = allow all
-  const db = getDb();
-  const row = db
-    .prepare(
-      `SELECT 1 FROM user_roles
-       WHERE user_id = ?
-         AND (role = 'owner' OR role = 'admin')
-         AND (agent_group_id IS NULL OR agent_group_id = ?)
-       LIMIT 1`,
-    )
-    .get(userId, agentGroupId);
-  return row != null;
+  return hasAdminPrivilege(userId, agentGroupId);
 }