feat(deploy): 在线更新 - 新增后台检查、强制备份迁移与失败自动回退

backend/internal/buildinfo/buildinfo.go

@@ -0,0 +1,49 @@
+package buildinfo
+
+import (
+	"runtime"
+	"runtime/debug"
+	"strings"
+)
+
+var (
+	Version   = "dev"
+	Commit    = "unknown"
+	BuildTime = "unknown"
+)
+
+type Info struct {
+	Version   string `json:"version"`
+	Commit    string `json:"commit"`
+	BuildTime string `json:"buildTime"`
+	GoVersion string `json:"goVersion"`
+}
+
+func Current() Info {
+	version := normalized(Version, "dev")
+	commit := normalized(Commit, "unknown")
+	buildTime := normalized(BuildTime, "unknown")
+	if info, ok := debug.ReadBuildInfo(); ok {
+		for _, setting := range info.Settings {
+			switch setting.Key {
+			case "vcs.revision":
+				if commit == "unknown" {
+					commit = normalized(setting.Value, commit)
+				}
+			case "vcs.time":
+				if buildTime == "unknown" {
+					buildTime = normalized(setting.Value, buildTime)
+				}
+			}
+		}
+	}
+	return Info{Version: version, Commit: commit, BuildTime: buildTime, GoVersion: runtime.Version()}
+}
+
+func normalized(value string, fallback string) string {
+	value = strings.TrimSpace(value)
+	if value == "" {
+		return fallback
+	}
+	return value
+}

backend/internal/buildinfo/buildinfo_test.go

@@ -0,0 +1,17 @@
+package buildinfo
+
+import "testing"
+
+func TestCurrentUsesInjectedValues(t *testing.T) {
+	previousVersion, previousCommit, previousBuildTime := Version, Commit, BuildTime
+	t.Cleanup(func() { Version, Commit, BuildTime = previousVersion, previousCommit, previousBuildTime })
+	Version, Commit, BuildTime = " v1.2.3 ", " abc123 ", " 2026-08-30T00:00:00Z "
+
+	info := Current()
+	if info.Version != "v1.2.3" || info.Commit != "abc123" || info.BuildTime != "2026-08-30T00:00:00Z" {
+		t.Fatalf("unexpected build info: %#v", info)
+	}
+	if info.GoVersion == "" {
+		t.Fatal("Go version should be populated")
+	}
+}