feat(P3.6): lock feature story task body edits when milestone is freeze/undergoing/completed/closed

app/api/routers/milestones.py

@@ -173,9 +173,9 @@ def create_milestone_task(project_id: int, milestone_id: int, task_data: schemas
     task = Task(
         title=data.get("title"),
         description=data.get("description"),
-        task_type=data.get("task_type", "task"),
+        task_type=data.get("task_type", "issue"),
         task_subtype=data.get("task_subtype"),
-        status=TaskStatus.OPEN,
+        status=TaskStatus.PENDING,
         priority=TaskPriority.MEDIUM,
         project_id=project_id,
         milestone_id=milestone_id,

app/api/routers/tasks.py

@@ -209,6 +209,21 @@ def update_task(task_id: int, task_update: schemas.TaskUpdate, db: Session = Dep
     body_fields = {k for k in update_data.keys() if k not in _always_allowed}
 
     if body_fields:
+        # P3.6 supplement: feature story tasks locked after milestone freeze
+        task_type = task.task_type.value if hasattr(task.task_type, 'value') else (task.task_type or "")
+        task_subtype = task.task_subtype or ""
+        if task_type == "story" and task_subtype == "feature" and task.milestone_id:
+            from app.models.milestone import Milestone
+            ms = db.query(Milestone).filter(Milestone.id == task.milestone_id).first()
+            if ms:
+                ms_status = ms.status.value if hasattr(ms.status, 'value') else ms.status
+                if ms_status in ("freeze", "undergoing", "completed", "closed"):
+                    raise HTTPException(
+                        status_code=400,
+                        detail=f"Feature story task cannot be edited: milestone is '{ms_status}'. "
+                               f"Blocked fields: {sorted(body_fields)}",
+                    )
+
         # undergoing/completed/closed: body edits forbidden
         if current_status in ("undergoing", "completed", "closed"):
             raise HTTPException(

app/models/models.py

@@ -7,7 +7,7 @@ import enum
 
 
 class TaskType(str, enum.Enum):
-    """Task type enum — 'issue' is a subtype of task, not the other way around."""
+    """Task type enum."""
     ISSUE = "issue"
     MAINTENANCE = "maintenance"
     RESEARCH = "research"
@@ -15,7 +15,6 @@ class TaskType(str, enum.Enum):
     STORY = "story"
     TEST = "test"
     RESOLUTION = "resolution"
-    TASK = "task"
 
 
 class TaskStatus(str, enum.Enum):