Add inline block editing to schedule templates

- Backend: PATCH /api/schedules/{template_id}/blocks/{block_id} endpoint
- Frontend: Edit button on each block row expands an inline form
  pre-filled with current subject, times, and label; saves via PATCH

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/app/routers/schedules.py

@@ -11,6 +11,7 @@ from app.schemas.schedule import (
     ScheduleTemplateOut,
     ScheduleTemplateUpdate,
     ScheduleBlockCreate,
+    ScheduleBlockUpdate,
     ScheduleBlockOut,
 )
 
@@ -144,6 +145,34 @@ async def add_block(
     return block
 
 
+@router.patch("/{template_id}/blocks/{block_id}", response_model=ScheduleBlockOut)
+async def update_block(
+    template_id: int,
+    block_id: int,
+    body: ScheduleBlockUpdate,
+    current_user: User = Depends(get_current_user),
+    db: AsyncSession = Depends(get_db),
+):
+    result = await db.execute(
+        select(ScheduleBlock)
+        .join(ScheduleTemplate)
+        .where(
+            ScheduleBlock.id == block_id,
+            ScheduleBlock.template_id == template_id,
+            ScheduleTemplate.user_id == current_user.id,
+        )
+    )
+    block = result.scalar_one_or_none()
+    if not block:
+        raise HTTPException(status_code=404, detail="Block not found")
+
+    for field, value in body.model_dump(exclude_unset=True).items():
+        setattr(block, field, value)
+    await db.commit()
+    await db.refresh(block)
+    return block
+
+
 @router.delete("/{template_id}/blocks/{block_id}", status_code=status.HTTP_204_NO_CONTENT)
 async def delete_block(
     template_id: int,