feat(task): 完善任务系统 —— 分类字典/字段/四种接单方式/独占限额/交付时限

- Task 加 published_at/delivery_days/headcount/exclusive/publisher_id/category_id；新增 TaskCategory 分类字典表(35 类)。
- mode 归一 grab/bid/assign/recommend(旧 designated→assign、dispatch→recommend)；TaskService 加 assign/recommend/select_recommend，claim 支持独占/限额、published+claimed 均可抢(多人)。
- TaskClaim 支持 source=assign/recommend、status=assigned/recommended/withdrawn + count_active_by_task；TaskCategoryRepository；Database 装配 task_categories。
- 端口：operator GET /admin/task-categories + POST tasks/{id}/assign|recommend|select；opc 同；park /api/tasks 返回 mode/deadline/delivery_days/headcount/exclusive/publisher_name。
- 迁移 0009(tasks 加列+task_categories)已应用+stamp；seed 35 分类字典 + task 新字段(含独占/推荐演示) + 补种已初始化库。
- 测试 test_task_system.py(独占/限额/指派/推荐/list_published/publish/category)+补齐 test_task_claim 语义, 15 passed。

Co-Authored-By: Claude <noreply@anthropic.com>

app/api/schemas/opc.py

@@ -10,6 +10,18 @@ class TaskClaimRequest(BaseModel):
     task_id: str = ""
 
 
+class TaskAssignRequest(BaseModel):
+    taker_user_id: str
+
+
+class TaskRecommendRequest(BaseModel):
+    candidates: list[str] = []
+
+
+class TaskSelectRecommendRequest(BaseModel):
+    taker_user_id: str = ""
+
+
 
 class ProfileUpdate(BaseModel):
     nickname: str | None = None

app/api/schemas/operator.py

@@ -3,21 +3,27 @@ from pydantic import BaseModel
 class TaskCreateRequest(BaseModel):
     title: str
     category: str = ""
+    category_id: str | None = None
     sub_category: str = ""
     description: str = ""
     tags: str = ""
-    mode: str = "grab"
+    mode: str = "grab"   # grab/bid/assign/recommend
     budget_min: int = 0
     budget_max: int = 0
     deadline: str = ""
+    delivery_days: int = 0
+    headcount: int = 0
+    exclusive: bool = False
     task_code: str = ""
     display_priority: int = 0
+    publisher_id: str | None = None
     publisher_name: str = ""
 
 
 class TaskUpdateRequest(BaseModel):
     title: str | None = None
     category: str | None = None
+    category_id: str | None = None
     sub_category: str | None = None
     description: str | None = None
     tags: str | None = None
@@ -25,8 +31,12 @@ class TaskUpdateRequest(BaseModel):
     budget_min: int | None = None
     budget_max: int | None = None
     deadline: str | None = None
+    delivery_days: int | None = None
+    headcount: int | None = None
+    exclusive: bool | None = None
     task_code: str | None = None
     display_priority: int | None = None
+    publisher_id: str | None = None
     publisher_name: str | None = None
 
 
@@ -34,6 +44,26 @@ class TaskStatusRequest(BaseModel):
     status: str  # review/published/completed/cancelled/claimed/doing
 
 
+class TaskAssignRequest(BaseModel):
+    taker_user_id: str
+
+
+class TaskRecommendRequest(BaseModel):
+    candidates: list[str] = []
+
+
+class TaskSelectRecommendRequest(BaseModel):
+    taker_user_id: str
+
+
+class TaskCategoryItem(BaseModel):
+    id: str
+    name: str
+    sort: int = 0
+    modes: str = ""
+    status: str = "active"
+
+
 
 class ProviderCreateRequest(BaseModel):
     name: str