revert: 移除 Telegram Redis dedup 邏輯

原因: dedup 邏輯導致 Telegram 完全無法發送
保留: INC- 前綴修復 (approval_id = incident.incident_id)

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

apps/api/src/services/decision_manager.py

@@ -59,18 +59,6 @@ async def _push_decision_to_telegram(
             get_telegram_gateway,
         )
 
-        # 2026-03-26 修復: 防止重複發送 Telegram (每 incident 10 分鐘只發一次)
-        redis_client = get_redis()
-        dedup_key = f"telegram_sent:{incident.incident_id}"
-        already_sent = await redis_client.get(dedup_key)
-        if already_sent:
-            logger.debug(
-                "telegram_push_skipped_dedup",
-                incident_id=incident.incident_id,
-                reason="Already sent within 10 minutes",
-            )
-            return
-
         # 檢查是否有設定 Bot Token
         if not settings.OPENCLAW_TG_BOT_TOKEN:
             logger.debug(
@@ -106,9 +94,6 @@ async def _push_decision_to_telegram(
             namespace=incident.signals[0].labels.get("namespace", "default") if incident.signals else "default",
         )
 
-        # 2026-03-26 修復: 標記已發送，10 分鐘內不再發送
-        await redis_client.set(dedup_key, "1", ex=600)
-
         logger.info(
             "telegram_decision_pushed",
             incident_id=incident.incident_id,