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.

types.ts

@@ -7,6 +7,14 @@ export enum FunnelStage {
   LOST = 'Perdidos',
 }
 
+export interface FunnelStageDef {
+  id: string;
+  tenant_id: string;
+  name: string;
+  color_class: string;
+  order_index: number;
+}
+
 export interface User {
   id: string;
   tenant_id: string;