fix: add collector role to API endpoints for mobile dashboard access

Collector users were blocked from ticket, payment, invoice, and client
endpoints requiring 'technician' role. Added 'collector' to @Roles
decorators and the COLLECTOR role to the shared role hierarchy.

src/invoice/invoice.controller.ts

@@ -20,7 +20,7 @@ export class InvoiceController {
   constructor(private readonly invoiceService: InvoiceService) {}
 
   @Get()
-  @Roles('technician')
+  @Roles('technician', 'collector')
   async findAll(
     @CurrentUser() user: CurrentUserPayload,
     @Query('clientId') clientId?: string,
@@ -30,7 +30,7 @@ export class InvoiceController {
   }
 
   @Get(':id')
-  @Roles('technician')
+  @Roles('technician', 'collector')
   async findById(
     @CurrentUser() user: CurrentUserPayload,
     @Param('id') id: string,