Subtasks: load subtasks + parent in task_out

- selectinload(Task.subtasks), joinedload(Task.parent) in _get_task + list_tasks
- SubtaskBrief schema: id, key, title, status, assignee
- TaskOut: subtasks list, parent_key, parent_title
- .unique() for joinedload dedup

src/tracker/api/converters.py

@@ -10,6 +10,7 @@ from .schemas import (
     MessageOut,
     ProjectFileOut,
     StepOut,
+    SubtaskBrief,
     TaskOut,
 )
 
@@ -95,6 +96,25 @@ def message_out(m: Message) -> MessageOut:
 
 def task_out(t: Task, project_slug: str = "") -> TaskOut:
     prefix = project_slug[:2].upper() if project_slug else "XX"
+
+    # Subtasks
+    subtasks = []
+    for sub in (t.subtasks or []):
+        subtasks.append(SubtaskBrief(
+            id=str(sub.id),
+            key=f"{prefix}-{sub.number}",
+            title=sub.title,
+            status=sub.status,
+            assignee=member_brief(sub.assignee) if sub.assignee else None,
+        ))
+
+    # Parent info
+    parent_key = None
+    parent_title = None
+    if t.parent:
+        parent_key = f"{prefix}-{t.parent.number}"
+        parent_title = t.parent.title
+
     return TaskOut(
         id=str(t.id),
         project_id=str(t.project_id),
@@ -116,6 +136,9 @@ def task_out(t: Task, project_slug: str = "") -> TaskOut:
         position=t.position,
         time_spent=t.time_spent,
         steps=[step_out(s) for s in (t.steps or [])],
+        subtasks=subtasks,
+        parent_key=parent_key,
+        parent_title=parent_title,
         created_at=t.created_at.isoformat() if t.created_at else "",
         updated_at=t.updated_at.isoformat() if t.updated_at else "",
     )

src/tracker/api/schemas.py

@@ -47,10 +47,21 @@ class TaskOut(BaseModel):
     position: int
     time_spent: int
     steps: list[StepOut] = []
+    subtasks: list["SubtaskBrief"] = []
+    parent_key: str | None = None
+    parent_title: str | None = None
     created_at: str
     updated_at: str
 
 
+class SubtaskBrief(BaseModel):
+    id: str
+    key: str
+    title: str
+    status: str
+    assignee: MemberBrief | None = None
+
+
 class MessageOut(BaseModel):
     id: str
     chat_id: str | None = None

src/tracker/api/tasks.py

@@ -189,12 +189,14 @@ async def _get_task(task_id: str, db: AsyncSession) -> Task:
         select(Task).where(Task.id == uuid.UUID(task_id))
         .options(
             selectinload(Task.steps),
+            selectinload(Task.subtasks).joinedload(Task.assignee),
             joinedload(Task.project),
             joinedload(Task.assignee),
             joinedload(Task.reviewer),
+            joinedload(Task.parent),
         )
     )
-    task = result.scalar_one_or_none()
+    task = result.unique().scalar_one_or_none()
     if not task:
         raise HTTPException(404, "Task not found")
     return task
@@ -221,9 +223,11 @@ async def list_tasks(
 ):
     q = select(Task).options(
         selectinload(Task.steps),
+        selectinload(Task.subtasks).joinedload(Task.assignee),
         joinedload(Task.project),
         joinedload(Task.assignee),
         joinedload(Task.reviewer),
+        joinedload(Task.parent),
     )
     if project_id:
         q = q.where(Task.project_id == uuid.UUID(project_id))
@@ -235,7 +239,7 @@ async def list_tasks(
         q = q.where(Task.labels.contains([label]))
     q = q.order_by(Task.position, Task.created_at)
     result = await db.execute(q)
-    return [task_out(t, t.project.slug if t.project else "") for t in result.scalars()]
+    return [task_out(t, t.project.slug if t.project else "") for t in result.unique().scalars()]
 
 
 @router.get("/tasks/{task_id}", response_model=TaskOut)