Add per-project Department management

Departments are now a customizable per-project list (standard + custom),
matching the existing custom task type/status pattern, instead of a fixed
7-value enum. They're usable directly on tasks (new field, independent of
assignee) and continue to drive team member department roles.

frontend/src/services/project.ts

@@ -26,7 +26,7 @@ export interface ProjectMember {
   id: number
   user_id: number
   project_id: number
-  department_role?: 'layout' | 'animation' | 'lighting' | 'composite' | 'modeling' | 'rigging' | 'surfacing'
+  department_role?: string
   joined_at: string
   user_email: string
   user_first_name: string
@@ -58,11 +58,11 @@ export interface ProjectUpdate {
 
 export interface ProjectMemberCreate {
   user_id: number
-  department_role?: 'layout' | 'animation' | 'lighting' | 'composite' | 'modeling' | 'rigging' | 'surfacing'
+  department_role?: string
 }
 
 export interface ProjectMemberUpdate {
-  department_role?: 'layout' | 'animation' | 'lighting' | 'composite' | 'modeling' | 'rigging' | 'surfacing'
+  department_role?: string
 }
 
 export interface DeliveryMovieSpec {