Refactor get_status and create_archive_task error handling

Raise exceptions instead of returning error messages from the worker in
create_arvive_task. This ensures consistency in how the errors are
presented on the task result: the Exception will be the result instead
of *maybe* being wrapped in an object like {error: Exception}.

This lets us simplify error handling in get_status so we have only one
try/except block where the error can be returned to the client.

src/worker.py

@@ -30,7 +30,9 @@ def get_db():
 def create_archive_task(self, archive_json: str):
     archive = schemas.ArchiveCreate.parse_raw(archive_json)
 
-    if (em := is_group_invalid_for_user(archive.public, archive.group_id, archive.author_id)): return {"error": em}
+    invalid = is_group_invalid_for_user(archive.public, archive.group_id, archive.author_id)
+    if (invalid):
+        raise Exception(invalid) # marks task FAILED, saves the Exception as reult
 
     url = archive.url
     logger.info(f"{url=} {archive=}")
@@ -40,9 +42,10 @@ def create_archive_task(self, archive_json: str):
     try:
         insert_result_into_db(result, archive.tags, archive.public, archive.group_id, archive.author_id, self.request.id)
     except Exception as e:
+        # Log it, then raise again to store the error as the task result
         logger.error(e)
         logger.error(traceback.format_exc())
-        return {"error": e}
+        raise e
     return result.to_dict()