Revert "refactor: clean up legacy code, rename hopper to entity_extractor, and add third-party notices"

This reverts commit 54fcef9887.

Please do not submit unrelated docs and codes in the same commit. I am reverting this commit so that the related files can be submitted in better-organized future commits.

artemis/controllers/unified_controller.py

@@ -11,9 +11,6 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-#
-# Portions of this file are derived from mobile-use (https://github.com/minitap-ai/mobile-use)
-# Copyright 2025-2026 Minitap, Inc. Licensed under the Apache License 2.0.
 
 import asyncio
 import os