fix: default task deadline to date only

backend/schemas.py

@@ -76,6 +76,7 @@ class TaskCreate(BaseModel):
     description: str = ""
     priority: int = Field(default=0, ge=0, le=3)
     due_at: datetime | None = None
+    due_has_time: bool = False
     parent_id: UUID | None = None
     rrule: str | None = Field(default=None, min_length=5, max_length=1000)
 
@@ -85,13 +86,14 @@ class TaskUpdate(BaseModel):
     description: str | None = None
     priority: int | None = Field(default=None, ge=0, le=3)
     due_at: datetime | None = None
+    due_has_time: bool | None = None
     completed: bool | None = None
     list_id: UUID | None = None
     version: int = Field(ge=1)
 
     @model_validator(mode="after")
     def reject_null_non_nullable_fields(self):
-        for field in ("title", "description", "priority", "completed", "list_id"):
+        for field in ("title", "description", "priority", "completed", "list_id", "due_has_time"):
             if field in self.model_fields_set and getattr(self, field) is None:
                 raise ValueError(f"{field} cannot be null")
         return self
@@ -117,6 +119,7 @@ class TaskOut(BaseModel):
     priority: int
     completed: bool
     due_at: datetime | None
+    due_has_time: bool
     version: int