fix(ssh-auto): 主機告警 SSH 自動診斷授權（HostHighCpuLoad 不再卡人工審核）

根因：SSH_MCP_ALLOWED_HOSTS 未設定 → _ssh_execute() 全部攔截
      + auto_approve 只認 kubectl 不認 ssh → 主機告警永遠降級人工

修復：
- ConfigMap: 補 SSH_MCP_ALLOWED_HOSTS 四主機白名單
- alert_rules: HostHighCpuLoad 等從 NO_ACTION 改為 ssh_diagnose 指令
- auto_approve: _has_executable 加入 ssh 開頭識別
- decision_manager: _ssh_execute() 加入 ssh_diagnose 路由
- ssh_provider: 新增 ssh_diagnose tool（ps aux + free -h + df -h，只讀）

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

apps/api/src/services/auto_approve.py

@@ -301,11 +301,19 @@ class AutoApprovePolicy:
         #                          P1-2 改用 NO_EXECUTABLE_ACTION（避免污染 KM 飛輪學習資料）
         _raw_action = proposal_data.get("action", "") or ""
         _kubectl_cmd = proposal_data.get("kubectl_command", "") or ""
-        _has_kubectl = "kubectl" in _raw_action.lower() or "kubectl" in _kubectl_cmd.lower()
-        if not _has_kubectl:
+        # 2026-04-27 Claude Sonnet 4.6: 擴充可執行指令識別，加入 SSH 診斷路徑
+        # 根因：_has_kubectl 只認 kubectl，SSH 診斷指令（主機告警）被全部攔截 → 飛輪停轉
+        # 修復：ssh {host} '...' 格式也是可執行指令，允許走 _ssh_execute() 路徑
+        _has_executable = (
+            "kubectl" in _raw_action.lower()
+            or "kubectl" in _kubectl_cmd.lower()
+            or _raw_action.lower().strip().startswith("ssh ")
+            or _kubectl_cmd.lower().strip().startswith("ssh ")
+        )
+        if not _has_executable:
             return self._reject(
                 reason=AutoApproveReason.NO_EXECUTABLE_ACTION,
-                detail=f"Action '{_raw_action[:60] or _kubectl_cmd[:60]}' is natural language — no kubectl command, requires human review",
+                detail=f"Action '{_raw_action[:60] or _kubectl_cmd[:60]}' is natural language — no kubectl/ssh command, requires human review",
                 risk_level=risk_level,
                 trust_score=trust_score,
                 confidence=confidence,

apps/api/src/services/decision_manager.py

@@ -3101,6 +3101,9 @@ class DecisionManager:
             return
 
         # 解析 SSH tool + params
+        # 2026-04-27 Claude Sonnet 4.6: 加入主機診斷路徑
+        # 根因：只支援 docker/systemctl restart，主機告警 ssh {host} '...' 格式全降級人工
+        # 修復：識別 ssh_diagnose 模式，路由到 ssh_get_top_processes / ssh_get_disk_usage
         _action_lower = action.lower().strip()
         if _action_lower.startswith("docker restart"):
             _tool = "docker_restart"
@@ -3108,6 +3111,9 @@ class DecisionManager:
         elif _action_lower.startswith("systemctl restart"):
             _tool = "service_restart"
             _service = target
+        elif _action_lower.startswith("ssh ") and ("ps aux" in _action_lower or "top" in _action_lower or "free" in _action_lower or "df -h" in _action_lower or "uptime" in _action_lower):
+            # 主機診斷指令：自動收集 CPU/記憶體/磁碟，不修改任何狀態
+            _tool = "ssh_diagnose"
         else:
             logger.info(
                 "ssh_execute_unknown_action",
@@ -3125,8 +3131,9 @@ class DecisionManager:
         params: dict = {"host": _host}
         if _tool == "docker_restart":
             params["container"] = _container
-        else:
+        elif _tool == "service_restart":
             params["service"] = _service
+        # ssh_diagnose: 只需 host，無額外 params
 
         try:
             result = await self._ssh.execute(tool_name=_tool, parameters=params)