feat(rag): Telegram /rag 指令 + /rag/optimize ivfflat 端點

- telegram_gateway: /rag <query> → KnowledgeRAGService.query()
  _handle_group_command 加 full_text 參數取得完整指令文字
  /help 更新加入 /rag 說明
- rag.py: POST /rag/optimize → rag_repo.create_ivfflat_index()
- rag_chunk_repository: create_ivfflat_index() — ivfflat with lists=100

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

apps/api/src/api/v1/rag.py

@@ -94,6 +94,13 @@ async def rag_stats() -> dict:
     return await svc.get_stats()
 
 
+@router.post("/optimize", summary="建立 ivfflat 向量索引（需 >100 chunks）", include_in_schema=False)
+async def rag_optimize() -> dict:
+    """對 rag_chunks.embedding 建立 ivfflat 索引，加速向量搜尋"""
+    import src.repositories.rag_chunk_repository as rag_repo
+    return await rag_repo.create_ivfflat_index()
+
+
 # ============================================================
 # Background helper
 # ============================================================

apps/api/src/repositories/rag_chunk_repository.py

@@ -88,6 +88,29 @@ async def delete_by_source_id(source_id: str) -> None:
         logger.warning("rag_chunk_delete_failed", source_id=source_id, error=str(e))
 
 
+async def create_ivfflat_index() -> dict:
+    """建立 ivfflat 向量索引（需 >100 chunks，加速 KNN 搜尋）"""
+    try:
+        async with get_db_context() as db:
+            await db.execute(
+                text("""
+                    CREATE INDEX IF NOT EXISTS idx_rag_chunks_embedding
+                    ON rag_chunks
+                    USING ivfflat (embedding vector_cosine_ops)
+                    WITH (lists = 100)
+                """)
+            )
+            rows = await db.execute(
+                text("SELECT indexname FROM pg_indexes WHERE tablename = 'rag_chunks'")
+            )
+            indexes = [r[0] for r in rows]
+        logger.info("rag_ivfflat_index_created", indexes=indexes)
+        return {"status": "ok", "indexes": indexes}
+    except Exception as e:
+        logger.error("rag_ivfflat_index_failed", error=str(e))
+        return {"status": "error", "error": str(e)}
+
+
 async def get_stats() -> dict:
     """取得 chunk 數量與來源統計"""
     try:

apps/api/src/services/telegram_gateway.py

@@ -3643,7 +3643,7 @@ class TelegramGateway:
         # ── 指令路由 (2026-04-03 ogt: 方案B slash commands) ──────────────────
         cmd = text.strip().split()[0].lower().split("@")[0] if text.strip() else ""
         if cmd.startswith("/"):
-            await self._handle_group_command(cmd, chat_id, message_id)
+            await self._handle_group_command(cmd, chat_id, message_id, full_text=text.strip())
             return
 
         from src.services.chat_manager import get_chat_manager as _get_cm
@@ -3729,7 +3729,7 @@ class TelegramGateway:
 
         logger.info("group_message_handled", user_id=user_id, text=text[:50])
 
-    async def _handle_group_command(self, cmd: str, _chat_id: int, message_id: int | None) -> None:
+    async def _handle_group_command(self, cmd: str, _chat_id: int, message_id: int | None, full_text: str = "") -> None:
         """
         SRE 群組 Slash Commands (2026-04-03 ogt: 方案B)
 
@@ -3737,6 +3737,7 @@ class TelegramGateway:
         /incidents → 活躍告警列表
         /cost      → 本月 AI 費用統計
         /pods      → 異常 Pod 列表
+        /rag       → RAG 知識庫查詢 (ADR-067 Phase 33)
         /help      → 指令說明
         """
         from src.repositories.k8s_repository import get_k8s_repository
@@ -3810,6 +3811,31 @@ class TelegramGateway:
                 msg = f"<b>⚠️ 異常 Pod</b>\n⚠️ 無法取得: {e}"
             await self.send_as_openclaw(text=msg, reply_to_message_id=message_id)
 
+        elif cmd == "/rag":
+            # /rag <查詢內容> — RAG 知識庫語義查詢 (ADR-067 Phase 33)
+            # 2026-04-10 Claude Sonnet 4.6 Asia/Taipei
+            parts = full_text.split(None, 1)
+            if len(parts) < 2 or not parts[1].strip():
+                await self.send_as_openclaw(
+                    text="<b>📚 RAG 知識庫查詢</b>\n用法: <code>/rag 你的問題</code>\n例如: <code>/rag 什麼是 ADR-067？</code>",
+                    reply_to_message_id=message_id,
+                )
+                return
+            question = parts[1].strip()
+            await self.send_as_openclaw(
+                text=f"<b>📚 查詢知識庫中...</b>\n<code>{question[:80]}</code>",
+                reply_to_message_id=message_id,
+            )
+            try:
+                from src.services.knowledge_rag_service import get_knowledge_rag_service
+                svc = get_knowledge_rag_service()
+                answer = await svc.query(question, top_k=5)
+                msg = f"<b>📚 RAG 知識庫</b>\n<i>Q: {question[:80]}</i>\n\n{answer}"
+            except Exception as e:
+                logger.warning("rag_telegram_query_failed", error=str(e))
+                msg = f"<b>📚 RAG 查詢失敗</b>\n{e}"
+            await self.send_as_openclaw(text=msg, reply_to_message_id=message_id)
+
         elif cmd == "/help":
             msg = (
                 "<b>🤖 SRE 戰情室指令</b>\n\n"
@@ -3817,6 +3843,7 @@ class TelegramGateway:
                 "/incidents — 列出活躍告警\n"
                 "/cost — 查詢本月 AI 費用\n"
                 "/pods — 列出異常 Pod\n"
+                "/rag &lt;問題&gt; — 查詢 RAG 知識庫\n"
                 "/help — 顯示此說明\n\n"
                 "<b>對話方式:</b>\n"
                 "• 直接輸入 → 小O + 小賀 同時回應\n"