feat: AI 서비스 및 AI 어시스턴트 전용 페이지 추가

- ai-service: Ollama 기반 AI 서비스 (분류, 시맨틱 검색, RAG Q&A, 패턴 분석)
- AI 어시스턴트 페이지: 채팅형 Q&A, 시맨틱 검색, 패턴 분석, 분류 테스트
- 권한 시스템에 ai_assistant 페이지 등록 (기본 비활성)
- 기존 페이지에 AI 기능 통합 (대시보드, 수신함, 관리함)
- docker-compose, gateway, nginx 설정 업데이트

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

ai-service/routers/rag.py

@@ -0,0 +1,57 @@
+from fastapi import APIRouter
+from pydantic import BaseModel
+from services.rag_service import (
+    rag_suggest_solution,
+    rag_ask,
+    rag_analyze_pattern,
+    rag_classify_with_context,
+)
+
+router = APIRouter(tags=["rag"])
+
+
+class AskRequest(BaseModel):
+    question: str
+    project_id: int | None = None
+
+
+class PatternRequest(BaseModel):
+    description: str
+    n_results: int = 10
+
+
+class ClassifyRequest(BaseModel):
+    description: str
+    detail_notes: str = ""
+
+
+@router.post("/rag/suggest-solution/{issue_id}")
+async def suggest_solution(issue_id: int):
+    try:
+        return await rag_suggest_solution(issue_id)
+    except Exception as e:
+        return {"available": False, "error": str(e)}
+
+
+@router.post("/rag/ask")
+async def ask_question(req: AskRequest):
+    try:
+        return await rag_ask(req.question, req.project_id)
+    except Exception as e:
+        return {"available": False, "error": str(e)}
+
+
+@router.post("/rag/pattern")
+async def analyze_pattern(req: PatternRequest):
+    try:
+        return await rag_analyze_pattern(req.description, req.n_results)
+    except Exception as e:
+        return {"available": False, "error": str(e)}
+
+
+@router.post("/rag/classify")
+async def classify_with_rag(req: ClassifyRequest):
+    try:
+        return await rag_classify_with_context(req.description, req.detail_notes)
+    except Exception as e:
+        return {"available": False, "error": str(e)}