Implement Phase 12 feedback, Phase 13 Semantic Chunker, Phase 13-B Reranker, Bug 5 thinking fix

- Phase 12: FeedbackRepository + td_feedback 테이블, Gradio 👍/👎 이벤트, run_id 추적, LangSmith create_feedback() 연동
- Phase 13: 커스텀 _SemanticSplitter 제거 → langchain_experimental.SemanticChunker 교체, buffer_size/threshold_type 환경변수 적용
- Phase 13-B: RerankService (Cross-Encoder), RetrieverService.search()에 reranker 통합, tools.py as_retriever() → search() 전환
- Bug 5: mlx_chat_model enable_thinking 런타임 오버라이드, agent_service stream_mode=["messages","custom"] 이중 스트림, thinking 토큰 custom 이벤트로 emit
- ROADMAP: LLM 모델명 8B 반영, RAG에 Reranker 추가, 추천 진행 순서 갱신

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

container.py

@@ -9,11 +9,13 @@ from services.chat.compact_service import CompactService
 from services.db.mysql_service import DatabaseService
 from services.db.conversation_repository import ConversationRepository
 from services.db.user_profile_repository import UserProfileRepository
+from services.db.feedback_repository import FeedbackRepository
 from services.ui.cli_service import CliUiService
 from services.events.event_bus import EventBus
 from services.events.handlers import StreamTokenHandler, StreamEndHandler
 from langchain_huggingface import HuggingFaceEmbeddings
 from services.rag.ingestion_service import IngestionService
+from services.rag.rerank_service import RerankService
 from services.rag.retriever_service import RetrieverService
 from services.agent.agent_service import AgentService
 
@@ -60,6 +62,11 @@ class Container(containers.DeclarativeContainer):
         db=db_service,
     )
 
+    feedback_repository = providers.Singleton(
+        FeedbackRepository,
+        db=db_service,
+    )
+
     history_service = providers.Factory(
         HistoryService,
         system_prompt=providers.Callable(lambda c: c.system_prompt, config),
@@ -97,6 +104,12 @@ class Container(containers.DeclarativeContainer):
         breakpoint_threshold_type=providers.Callable(
             lambda c: c.semantic_breakpoint_threshold_type, config
         ),
+        buffer_size=providers.Callable(lambda c: c.semantic_buffer_size, config),
+    )
+
+    reranker = providers.Callable(
+        lambda c: RerankService(c.reranker_model_id) if c.reranker_enabled else None,
+        config,
     )
 
     retriever_service = providers.Singleton(
@@ -105,6 +118,8 @@ class Container(containers.DeclarativeContainer):
         qdrant_url=providers.Callable(lambda c: c.qdrant_url, config),
         collection_name=providers.Callable(lambda c: c.qdrant_collection, config),
         top_k=providers.Callable(lambda c: c.rag_top_k, config),
+        reranker=reranker,
+        rerank_fetch_k=providers.Callable(lambda c: c.reranker_fetch_k, config),
     )
 
     # Phase 3 — LangGraph Agent