Phase 28: P3 — Pydantic Settings, dependency-injector IoC, tenacity retry

- config.py: dataclasses → pydantic-settings BaseSettings (flat AppConfig,
  env vars auto-loaded from .env, type-safe validation)
- api_client.py: HTTPAPIClient takes AppConfig directly (APIConfig removed);
  tenacity retry on 5 methods (reset/ingest/list/delete/feedback) —
  retries on 5xx + TransportError, 3 attempts, exponential backoff 1-8s
- container.py: manual DI → dependency_injector DeclarativeContainer with
  providers.Singleton; Container() needs no args
- app.py: container.X → container.X() calls, remove AppConfig import
- requirements.txt: add pydantic-settings, tenacity, dependency-injector

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

app.py

@@ -23,10 +23,9 @@ logging.basicConfig(
 )
 logger = logging.getLogger(__name__)
 
-from config import AppConfig
 from container import Container
 
-container = Container(AppConfig())
+container = Container()
 
 USER_LABELS = ["아록", "근혜", "도율", "하율"]
 DEFAULT_USER = "아록"
@@ -39,7 +38,7 @@ def _get_whisper():
     global _whisper_model
     if _whisper_model is None:
         import whisper
-        _whisper_model = whisper.load_model(container.config.whisper_model_size)
+        _whisper_model = whisper.load_model(container.config().whisper_model_size)
     return _whisper_model
 
 
@@ -71,7 +70,7 @@ async def respond(message, history, show_thinking, user_id, use_tts, run_ids):
     thinking_finalized = False
 
     try:
-        async for token, run_id in container.chat_service.chat(message, user_id, show_thinking):
+        async for token, run_id in container.chat_service().chat(message, user_id, show_thinking):
             if run_id is not None:
                 collected_run_id = run_id
                 break
@@ -120,7 +119,7 @@ async def respond(message, history, show_thinking, user_id, use_tts, run_ids):
     run_ids.append(collected_run_id)
 
     if use_tts:
-        audio_path = await container.tts_service.speak(tts_text)
+        audio_path = await container.tts_service().speak(tts_text)
         yield history, "", audio_path, run_ids, gr.update(), gr.update()
     else:
         yield history, "", None, run_ids, gr.update(), gr.update()
@@ -142,7 +141,7 @@ async def handle_feedback(like_data: gr.LikeData, history, run_ids, user_id):
     rating = 1 if like_data.liked else -1
 
     try:
-        await container.chat_service.save_feedback(user_id, user_msg, asst_msg, rating, run_id)
+        await container.chat_service().save_feedback(user_id, user_msg, asst_msg, rating, run_id)
     except Exception as e:
         logger.error("피드백 저장 실패: %s", e)
 
@@ -153,7 +152,7 @@ def switch_user(user_id):
 
 async def reset_chat(user_id):
     try:
-        await container.chat_service.reset(user_id)
+        await container.chat_service().reset(user_id)
     except Exception as e:
         logger.error("대화 초기화 실패: %s", e)
     return [], []
@@ -168,7 +167,7 @@ async def ingest_files(files):
     results = []
     for path in paths:
         try:
-            result = await container.document_service.ingest(path)
+            result = await container.document_service().ingest(path)
             name = os.path.basename(path)
             results.append(f"{name} → {result.get('chunks', '?')}개 청크")
         except Exception as e:
@@ -178,7 +177,7 @@ async def ingest_files(files):
 
 async def list_docs():
     try:
-        sources = await container.document_service.list_documents()
+        sources = await container.document_service().list_documents()
         return [[os.path.basename(s), s] for s in sources]
     except Exception as e:
         return [[f"오류: {e}", ""]]
@@ -188,7 +187,7 @@ async def delete_doc(source):
     if not source.strip():
         return "삭제할 파일 경로를 입력하세요.", await list_docs()
     try:
-        await container.document_service.delete_document(source.strip())
+        await container.document_service().delete_document(source.strip())
         return f"삭제 완료: {os.path.basename(source.strip())}", await list_docs()
     except Exception as e:
         return f"오류: {e}", await list_docs()
@@ -365,7 +364,7 @@ with gr.Blocks(title="율봇") as demo:
 
 if __name__ == "__main__":
     demo.launch(
-        server_name=container.config.server_host,
-        server_port=container.config.server_port,
+        server_name=container.config().server_host,
+        server_port=container.config().server_port,
         theme=gr.themes.Soft(),
     )