fix(pipeline): 三斷點修復 — SLO公式+NO_ACTION堆積+幻覺降級風險

D1 flywheel_stats_service: execution_count 欄位不存在 → 改讀
    success_count+failure_count；消除飛輪執行成功率永遠 0.0% 假象

D2 openclaw._validate_deployment_inventory: 幻覺 deployment 降級後
    原 HIGH/CRITICAL risk 未清零 → 加 result.risk_level = AIRiskLevel.LOW

D3 webhooks.py (兩處 alert path): NO_ACTION/INVESTIGATE/OBSERVE 三類
    非破壞性動作強制 risk_level = LOW，跳過 Telegram 批准直接 auto-approve
    → approval_execution.py 的 NO_ACTION handler 立即標 EXECUTION_SUCCESS

Root cause 鏈：BUTTON_DATA_INVALID 修復後 TG 按鈕可發，但 NO_ACTION
積壓的 35 筆 PENDING 是因 HIGH risk 無法走 auto-approve 路徑導致。

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

apps/api/src/services/flywheel_stats_service.py

@@ -204,9 +204,9 @@ class FlywheelStatsService:
                     status = pb.get("status", "")
                     if status == "approved":
                         count += 1
-                    exec_count = pb.get("execution_count", 0) or 0
                     success_count = pb.get("success_count", 0) or 0
-                    total_exec += exec_count
+                    failure_count = pb.get("failure_count", 0) or 0
+                    total_exec += success_count + failure_count
                     total_success += success_count
                 except (json.JSONDecodeError, KeyError):
                     continue

apps/api/src/services/openclaw.py

@@ -32,6 +32,7 @@ from src.core.config import settings
 from src.core.prompts import NEMOTRON_SYSTEM_PROMPT, OPENCLAW_SYSTEM_PROMPT
 from src.core.redis_client import get_redis
 from src.models.ai import (
+    AIRiskLevel,
     OpenClawDecision,
     SuggestedAction,
 )
@@ -1214,6 +1215,12 @@ class OpenClawService:
             result.confidence = 0.0
         except Exception:
             pass
+        # 2026-04-21 ogt: 降級後風險強制 LOW，避免 NO_ACTION 因原 HIGH/CRITICAL risk
+        # 留在 PENDING 等 Telegram 批准（已無執行內容，等待毫無意義）
+        try:
+            result.risk_level = AIRiskLevel.LOW
+        except Exception:
+            pass
 
     def _parse_analysis_result(self, raw_response: str) -> OpenClawDecision | None:
         """