fix(api): Telegram 去重 + 修復 INC-INC-INC- 重複前綴

- 加入 Redis 去重機制 (10 分鐘 TTL)
- 修復 approval_id 重複添加 INC- 前綴

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

apps/api/src/services/decision_manager.py

@@ -53,13 +53,26 @@ async def _push_decision_to_telegram(
     決策就緒時推送到 Telegram
 
     Phase 6.5: 整合 Signal Worker 流程與 Telegram 通知
+    2026-03-27 ogt: 加入 Redis 去重機制 (10 分鐘 TTL)
     """
     try:
         # 延遲導入避免循環依賴
+        from src.core.redis_client import get_redis
         from src.services.telegram_gateway import (
             get_telegram_gateway,
         )
 
+        # 🔴 去重檢查：同一個 incident 10 分鐘內只發一次
+        redis = get_redis()
+        dedup_key = f"telegram_sent:{incident.incident_id}"
+        if await redis.exists(dedup_key):
+            logger.debug(
+                "telegram_push_skipped",
+                reason="Already sent within 10 minutes",
+                incident_id=incident.incident_id,
+            )
+            return
+
         # 檢查是否有設定 Bot Token
         if not settings.OPENCLAW_TG_BOT_TOKEN:
             logger.debug(
@@ -81,7 +94,8 @@ async def _push_decision_to_telegram(
         source = proposal_data.get("source", "unknown")
 
         # 建立 approval_id (使用 incident_id 作為追蹤)
-        approval_id = f"INC-{incident.incident_id}"
+        # 2026-03-27 ogt: 修復 INC-INC-INC- 重複前綴 bug
+        approval_id = incident.incident_id  # 已經是 INC-xxx 格式
 
         await gateway.send_approval_card(
             approval_id=approval_id,
@@ -95,6 +109,9 @@ async def _push_decision_to_telegram(
             namespace=incident.signals[0].labels.get("namespace", "default") if incident.signals else "default",
         )
 
+        # 🔴 發送成功後設置去重 key (TTL 10 分鐘)
+        await redis.setex(dedup_key, 600, "1")
+
         logger.info(
             "telegram_decision_pushed",
             incident_id=incident.incident_id,