feat(alertmanager): Telegram Fallback 直送路徑 (ADR-035)

新增 telegram-direct receiver，critical 告警同時走：
1. awoooi-webhook (主路徑: AI 分析 + 去重)
2. telegram-direct (fallback: AWOOOI API 掛時直接通知)

continue:true 讓 critical route 同時匹配兩個 receiver。
warning 僅走 awoooi-webhook，避免雙重通知。

已在 110 熱重載驗證 (receivers: awoooi-webhook + telegram-direct)。

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

ops/alertmanager/alertmanager.yml

@@ -0,0 +1,87 @@
+# AWOOOI Alertmanager 配置
+# 2026-04-05 Claude Code: 修正 webhook URL
+# 修正前: http://192.168.0.188:8088/api/v1/webhook/alertmanager (OpenClaw，舊系統，錯誤)
+# 修正後: http://192.168.0.121:32334/api/v1/webhooks/alertmanager (AWOOOI API，複數，正確)
+# 根據 feedback_alertmanager_awoooi_flow.md 鐵律
+# 2026-04-09 Claude Sonnet 4.6 Asia/Taipei: 新增 Telegram Fallback (ADR-035)
+# 架構: awoooi-webhook (主路徑) + telegram-direct (fallback，獨立路由)
+# 當 AWOOOI API 無法回應時，critical 告警直接送 Telegram Bot API
+# ⚠️  bot_token/chat_id 部署時由 secrets 替換，此檔為模板
+
+global:
+  resolve_timeout: 5m
+
+route:
+  receiver: 'awoooi-webhook'
+  group_by: ['alertname', 'severity']
+  group_wait: 30s
+  group_interval: 5m
+  repeat_interval: 4h
+  routes:
+    - match:
+        severity: critical
+      receiver: 'awoooi-webhook'
+      group_wait: 10s
+      # continue:true 讓 critical 同時送 telegram-direct (fallback)
+      continue: true
+    - match:
+        severity: critical
+      receiver: 'telegram-direct'
+      group_wait: 10s
+    - match:
+        severity: warning
+      receiver: 'awoooi-webhook'
+    - match_re:
+        alertname: 'Zombie.*|Container.*'
+      receiver: 'awoooi-webhook'
+      group_wait: 1m
+
+receivers:
+  # 主路徑: AWOOOI API 處理所有告警 (AI 分析 + 去重 + Telegram)
+  - name: 'awoooi-webhook'
+    webhook_configs:
+      - url: 'http://192.168.0.121:32334/api/v1/webhooks/alertmanager'
+        send_resolved: true
+
+  # Fallback 路徑: AWOOOI API 掛掉時，critical 告警直接送 Telegram
+  # 只有 critical severity 走此路徑（避免 warning 雙重通知）
+  - name: 'telegram-direct'
+    telegram_configs:
+      - bot_token: 'TELEGRAM_BOT_TOKEN_PLACEHOLDER'
+        chat_id: TELEGRAM_CHAT_ID_PLACEHOLDER
+        parse_mode: 'HTML'
+        message: |
+          🚨 <b>[Alertmanager Fallback]</b>
+          {{ range .Alerts }}
+          ├ <b>{{ .Labels.alertname }}</b>
+          ├ 嚴重度: {{ .Labels.severity }}
+          ├ 主機: {{ .Labels.host }}{{ .Labels.instance }}
+          └ {{ .Annotations.summary }}
+          {{ end }}
+          <i>⚠️ AWOOOI API 可能離線，此為直接告警</i>
+        send_resolved: false
+
+inhibit_rules:
+  - source_match:
+      severity: critical
+    target_match:
+      severity: warning
+    equal: ['alertname', 'instance']
+  - source_match:
+      alertname: HostDown
+    target_match_re:
+      alertname: 'HostHighCpuLoad|HostOutOfMemory|HostOutOfDiskSpace'
+    equal: ['host']
+  - source_match:
+      alertname: KubeNodeNotReady
+    target_match_re:
+      alertname: 'KubePodCrashLooping|KubePodNotReady|KubeDeploymentReplicasMismatch'
+    equal: ['node']
+  - source_match:
+      alertname: PostgreSQLDown
+    target_match:
+      alertname: PostgreSQLHighConnections
+  - source_match:
+      alertname: RedisDown
+    target_match:
+      alertname: RedisMemoryHigh