fix(sre): type backup alerts before generic routing

apps/api/src/services/incident_service.py

@@ -146,17 +146,15 @@ def classify_alert_early(
 
     規則優先順序（由高到低）:
     1. ConfigurationDrift / KubeConfigDrift → TYPE-4D (Config Drift 卡片)
-    2. severity=info/none → TYPE-1 (純資訊，無按鈕)
-    3. backup/heartbeat 關鍵字 → TYPE-1（但 backup failure age > 24h → TYPE-3，見下）
+    2. backup/restore/escrow → backup_restore（成功 TYPE-1，其餘 TYPE-3 唯讀調查）
+    3. severity=info/none → TYPE-1 (純資訊，無按鈕)
     4. Docker/Host/Systemd runner 前綴 → infrastructure/host_resource TYPE-3
     5. Kube/Pod/Deploy/Node/Velero/ArgoCD 前綴 → kubernetes TYPE-3
     6. Postgres/Redis 前綴 → database TYPE-3
     7. 預設 → general TYPE-3
 
-    2026-04-25 ogt + Claude Sonnet 4.6 (P0 備份告警升級修復):
-    - age_hours > 24：HostBackupFailed/HostBackupStale/HostBackupMissing 升級為 TYPE-3
-      原因：備份 25h 未成功是 P0 故障，不是「純資訊」
-      此時應觸發 LLM 分析 + 自動修復建議，而非靜默發純文字通知
+    備份失敗不再以 age 延遲分類；立即進入不可寫入的 BackupCheck。
+    實際 backup/restore/retention/escrow 寫入仍屬 critical break-glass。
 
     C3 修正 (首席架構師 CR 2026-04-13): 從 Router 層 (webhooks.py) 移入 Service 層
     原違規: 業務邏輯函數定義在 api/v1/webhooks.py
@@ -220,6 +218,41 @@ def classify_alert_early(
     )):
         return "business", "TYPE-6B"
 
+    # Backup / restore / escrow is a typed data-protection domain.  Classify it
+    # before the generic info shortcut so successful receipts keep their
+    # domain label, while every non-info failure enters the read-only
+    # BackupCheck lane immediately instead of spending 24 hours as a generic
+    # or observation-only alert.  This only selects investigation/receipt
+    # semantics; production backup/restore writes remain critical break-glass.
+    backup_identity = " ".join(
+        (
+            alertname_lower,
+            str((labels or {}).get("event_type") or "").lower(),
+            str((labels or {}).get("lane") or "").lower(),
+            str((labels or {}).get("asset_domain") or "").lower(),
+        )
+    )
+    if any(
+        marker in backup_identity
+        for marker in (
+            "backup",
+            "escrow",
+            "restic",
+            "rclone",
+            "offsite",
+            "restore_drill",
+            "restore-drill",
+            "restoredrill",
+            "restore_test",
+            "restore-test",
+            "restoretest",
+        )
+    ):
+        return (
+            "backup_restore",
+            "TYPE-1" if severity in ("info", "none") else "TYPE-3",
+        )
+
     # 5. 純資訊
     if severity in ("info", "none"):
         return "info", "TYPE-1"
@@ -230,31 +263,12 @@ def classify_alert_early(
     if alertname.startswith("SystemdRunner"):
         return "host_resource", "TYPE-3"
 
-    # 5. Backup / Heartbeat — 純資訊，不進 LLM
-    # HostBackupFailed 必須在 Host prefix 前攔截，否則被歸 host_resource/TYPE-3
-    # 2026-04-12 ogt: 只針對已知主機備份監控 alertname，不用寬泛關鍵字
-    # BackupJobFailed severity=warning 仍走 TYPE-3（見測試 test_backup_keyword_warning_not_type1）
-    _BACKUP_TYPE1_NAMES = {
-        "HostBackupFailed", "HostBackupStale", "HostBackupMissing",
-        "BackupRestoreTestFailed", "BackupRestoreTestStale",
-    }
-    # 2026-04-25 ogt + Claude Sonnet 4.6 (P0 備份告警升級修復):
-    # 備份失敗 > 24h 不是「純資訊」，是 P0 故障，必須走 TYPE-3 觸發 LLM 分析 + 自動修復
-    # BackupRestoreTestFailed 屬測試驗證類，不受 age 升級影響（仍 TYPE-1）
-    _BACKUP_AGE_UPGRADE_NAMES = {
-        "HostBackupFailed", "HostBackupStale", "HostBackupMissing",
-    }
-    _BACKUP_AGE_THRESHOLD_HOURS = 24.0
-    if alertname in _BACKUP_AGE_UPGRADE_NAMES and age_hours > _BACKUP_AGE_THRESHOLD_HOURS:
-        return "backup_failure", "TYPE-3"
-
+    # 5. Heartbeat — 純資訊，不進 LLM。
     # 2026-04-12 ogt: 補入 DeadMansSwitch（HEARTBEAT_ALERT_NAMES 中但之前漏掉）
     if (
         "watchdog" in alertname_lower
         or "deadmansswitch" in alertname_lower
         or alertname == "Heartbeat"
-        or alertname in _BACKUP_TYPE1_NAMES
-        or alertname.startswith("HostBackup")
     ):
         return "backup", "TYPE-1"