Fix test failures and workload/websocket behavior

backend/app/schemas/task.py

@@ -35,6 +35,15 @@ class TaskBase(BaseModel):
     start_date: Optional[datetime] = None
     due_date: Optional[datetime] = None
 
+    @field_validator("title")
+    @classmethod
+    def title_not_blank(cls, value: str) -> str:
+        if value is None:
+            return value
+        if value.strip() == "":
+            raise ValueError("Title cannot be blank or whitespace")
+        return value
+
 
 class TaskCreate(TaskBase):
     parent_task_id: Optional[str] = None
@@ -57,6 +66,15 @@ class TaskUpdate(BaseModel):
     custom_values: Optional[List[CustomValueInput]] = None
     version: Optional[int] = Field(None, ge=1, description="Version for optimistic locking")
 
+    @field_validator("title")
+    @classmethod
+    def title_not_blank(cls, value: Optional[str]) -> Optional[str]:
+        if value is None:
+            return value
+        if value.strip() == "":
+            raise ValueError("Title cannot be blank or whitespace")
+        return value
+
 
 class TaskStatusUpdate(BaseModel):
     status_id: str
@@ -131,3 +149,8 @@ class TaskDeleteResponse(BaseModel):
     task: TaskResponse
     blockers_resolved: int = 0
     force_deleted: bool = False
+
+    @computed_field
+    @property
+    def id(self) -> str:
+        return self.task.id