fix(aiops): fallback and escalate automation blockers

apps/api/src/services/decision_manager.py

@@ -54,6 +54,26 @@ def _fire_and_forget(coro) -> asyncio.Task:
     return task
 
 
+def _phase2_fallback_reason(package: Any) -> str | None:
+    """Return why a Phase 2 package should continue to Playbook/LLM fallback.
+
+    Phase 2 is a deliberation layer, not the final brake. If the debate times
+    out or produces no actionable recommendation, the flywheel must still try
+    deterministic Playbook/LLM/expert paths before opening a manual gate.
+    """
+
+    status = getattr(package, "session_status", None)
+    status_value = status.value if status and hasattr(status, "value") else str(status or "")
+    if status_value in {"timeout", "failed"}:
+        return f"session_{status_value}"
+    if getattr(package, "all_agents_degraded", False):
+        return "all_agents_degraded"
+    action = str(getattr(package, "recommended_action", "") or "").strip()
+    if not action and getattr(package, "requires_human_approval", False):
+        return "empty_action_requires_human"
+    return None
+
+
 # =============================================================================
 # Phase 31 (ADR-067 2026-04-10): Log 異常摘要 — NemoTron deepseek-r1:14b
 # =============================================================================
@@ -2455,13 +2475,26 @@ class DecisionManager:
                 # evidence_snapshot 攜帶進 proposal_data，避免 singleton 並發污染
                 _p2_result = _package_to_proposal_data(package)
                 _p2_result["_evidence_snapshot_ref"] = p2_snapshot
-                return _p2_result
+                _p2_fallback = _phase2_fallback_reason(package)
+                if not _p2_fallback:
+                    return _p2_result
+
+                logger.warning(
+                    "p2_degraded_fallback_to_playbook_llm",
+                    incident_id=incident.incident_id,
+                    reason=_p2_fallback,
+                    confidence=_p2_result.get("confidence"),
+                    blocked_reason=_p2_result.get("blocked_reason", ""),
+                )
             # snapshot 仍為 None → 降級繼續走原路徑（不阻塞）
-            logger.warning("p2_no_snapshot_fallback", incident_id=incident.incident_id)
+            if p2_snapshot is None:
+                logger.warning("p2_no_snapshot_fallback", incident_id=incident.incident_id)
 
         # Phase 7.5: 先嘗試 Playbook 匹配
         playbook_result = await self._try_playbook_match(incident)
         if playbook_result:
+            if evidence_snapshot is not None:
+                playbook_result["_evidence_snapshot_ref"] = evidence_snapshot
             return playbook_result
 
         # MCP Phase 4c: Playbook 無命中 → 非同步產生 AI 草稿 Playbook (2026-04-11 Claude Sonnet 4.6)