feat: add code-first API support for projects, milestones, proposes, tasks

- Projects: get/update/delete/members endpoints now accept project_code
- Milestones: all project-scoped and top-level endpoints accept milestone_code
- Proposes: all endpoints accept project_code and propose_code
- Tasks: code-first support for all CRUD + transition + take + search
- Schemas: add code/type/due_date/project_code/milestone_code/taken_by fields
- All endpoints use id-or-code lookup helpers for backward compatibility
- Milestone serializer now includes milestone_code and code fields
- Task serializer enriches responses with project_code, milestone_code, taken_by

Addresses TODO §2.1: code-first API support across CLI-targeted resources

app/schemas/schemas.py

@@ -44,9 +44,12 @@ class TaskBase(BaseModel):
 
 class TaskCreate(TaskBase):
     project_id: Optional[int] = None
+    project_code: Optional[str] = None
     milestone_id: Optional[int] = None
+    milestone_code: Optional[str] = None
     reporter_id: Optional[int] = None
     assignee_id: Optional[int] = None
+    type: Optional[TaskTypeEnum] = None
     # Resolution specific
     resolution_summary: Optional[str] = None
     positions: Optional[str] = None
@@ -57,10 +60,12 @@ class TaskUpdate(BaseModel):
     title: Optional[str] = None
     description: Optional[str] = None
     task_type: Optional[TaskTypeEnum] = None
+    type: Optional[TaskTypeEnum] = None
     task_subtype: Optional[str] = None
     status: Optional[TaskStatusEnum] = None
     priority: Optional[TaskPriorityEnum] = None
     assignee_id: Optional[int] = None
+    taken_by: Optional[str] = None
     tags: Optional[str] = None
     estimated_effort: Optional[int] = None
     # Resolution specific
@@ -73,10 +78,16 @@ class TaskResponse(TaskBase):
     id: int
     status: TaskStatusEnum
     task_code: Optional[str] = None
+    code: Optional[str] = None
+    type: Optional[str] = None
+    due_date: Optional[datetime] = None
     project_id: int
+    project_code: Optional[str] = None
     milestone_id: int
+    milestone_code: Optional[str] = None
     reporter_id: int
     assignee_id: Optional[int] = None
+    taken_by: Optional[str] = None
     created_by_id: Optional[int] = None
     estimated_working_time: Optional[time] = None
     resolution_summary: Optional[str] = None