[改善] 型注釈の追加とドキュメントの更新

- config.py, controller.py, model.py, mainloop.py, utils.py での型注釈の追加
- CODING_RULES.md と api.md のドキュメントを更新
- 不要なコードの削除とリファクタリング

src-python/models/__init__.py

@@ -0,0 +1,5 @@
+"""models package init for static analysis and packaging."""
+
+__all__ = [
+    # subpackages are discovered implicitly
+]

src-python/models/overlay/__init__.py

@@ -0,0 +1,5 @@
+"""models.overlay package init for static analysis."""
+
+from . import overlay_utils  # re-export helper for ease-of-use in tooling
+
+__all__ = ["overlay_utils"]

src-python/models/transcription/transcription_recorder.py

@@ -1,7 +1,6 @@
 from speech_recognition import Recognizer, Microphone
 from pyaudiowpatch import get_sample_size, paInt16
 from datetime import datetime
-from queue import Queue
 
 class BaseRecorder:
     def __init__(self, source, energy_threshold, dynamic_energy_threshold, record_timeout):