feat(watchdog): 主机侧巡检定时器按异常邮件通知平台所有者，operator 增加 phase 与 build_info 指标、卡死存活探针与告警规则

cmd/felis/api.go

@@ -19,6 +19,7 @@ import (
 	"felis.lolicon.best/internal/fileedit"
 	"felis.lolicon.best/internal/imagepin"
 	"felis.lolicon.best/internal/mail"
+	"felis.lolicon.best/internal/metrics"
 	"felis.lolicon.best/internal/naming"
 	"felis.lolicon.best/internal/panel"
 	"felis.lolicon.best/internal/passkey"
@@ -110,6 +111,8 @@ func cmdAPI(args []string, stdout, stderr io.Writer) int {
 		return 1
 	}
 
+	metrics.SetBuildInfo("api", resolvedVersion())
+
 	token := os.Getenv("FELIS_SERVICE_TOKEN")
 	if token == "" {
 		fmt.Fprintln(stderr, "felis api: warning: FELIS_SERVICE_TOKEN unset — internal face will reject all callers")