feat: implement customizable funnel stages per tenant

- Modified attendances.funnel_stage in DB from ENUM to VARCHAR.

- Created tenant_funnels table and backend API routes to manage custom stages.

- Added /admin/funnels page for Admins/Managers to create, edit, order, and color-code their funnel stages.

- Updated Dashboard, UserDetail, and AttendanceDetail to fetch and render dynamic funnel stages instead of hardcoded enums.

- Added defensive checks and logging to GET /users/:idOrSlug to fix sporadic 500 errors during impersonation handoffs.

App.tsx

@@ -7,6 +7,7 @@ import { AttendanceDetail } from './pages/AttendanceDetail';
 import { SuperAdmin } from './pages/SuperAdmin';
 import { TeamManagement } from './pages/TeamManagement';
 import { Teams } from './pages/Teams';
+import { Funnels } from './pages/Funnels';
 import { Login } from './pages/Login';
 import { ForgotPassword } from './pages/ForgotPassword';
 import { ResetPassword } from './pages/ResetPassword';
@@ -76,6 +77,7 @@ const App: React.FC = () => {
         <Route path="/" element={<AuthGuard><Dashboard /></AuthGuard>} />
         <Route path="/admin/users" element={<AuthGuard roles={['super_admin', 'admin', 'manager']}><TeamManagement /></AuthGuard>} />
         <Route path="/admin/teams" element={<AuthGuard roles={['super_admin', 'admin', 'manager']}><Teams /></AuthGuard>} />
+        <Route path="/admin/funnels" element={<AuthGuard roles={['super_admin', 'admin', 'manager']}><Funnels /></AuthGuard>} />
         <Route path="/users/:id" element={<AuthGuard><UserDetail /></AuthGuard>} />
         <Route path="/attendances/:id" element={<AuthGuard><AttendanceDetail /></AuthGuard>} />
         <Route path="/super-admin" element={<AuthGuard roles={['super_admin']}><SuperAdmin /></AuthGuard>} />