feat(api): M-04 添加版本信息端点

- 添加 /version 端点返回版本信息
- 版本变量支持构建时 ldflags 注入
- 返回 version、commit、build_time、go_version

internal/app/http_api.go

@@ -10,6 +10,7 @@ import (
 	"net/http"
 	"os"
 	"path/filepath"
+	"runtime"
 	"strconv"
 	"strings"
 	"time"
@@ -25,6 +26,13 @@ import (
 	"sub2api-cn-relay-manager/internal/access"
 )
 
+// 版本信息变量，在构建时通过 -ldflags 注入
+var (
+	version   = "dev"
+	commit    = "unknown"
+	buildTime = "unknown"
+)
+
 type ActionSet struct {
 	CreateBatchImportRun                func(context.Context, CreateBatchImportRunRequest) (BatchImportRunCreateResponse, error)
 	ListBatchImportRuns                 func(context.Context, ListBatchImportRunsRequest) (ListBatchImportRunsResponse, error)
@@ -327,6 +335,7 @@ func NewAPIHandler(adminToken string, actions ActionSet) http.Handler {
 func NewAPIHandlerWithAuth(adminAuth AdminAuthConfig, actions ActionSet) http.Handler {
 	mux := http.NewServeMux()
 	mux.HandleFunc("GET /healthz", healthz)
+	mux.HandleFunc("GET /version", handleVersion)
 	mux.HandleFunc("GET /api/admin/session", func(w http.ResponseWriter, r *http.Request) {
 		handleAdminSessionState(w, r, adminAuth)
 	})
@@ -557,6 +566,24 @@ func healthz(w http.ResponseWriter, _ *http.Request) {
 	_, _ = w.Write([]byte("ok"))
 }
 
+// VersionInfo 包含版本信息响应
+type VersionInfo struct {
+	Version   string `json:"version"`
+	Commit    string `json:"commit"`
+	BuildTime string `json:"build_time"`
+	GoVersion string `json:"go_version"`
+}
+
+func handleVersion(w http.ResponseWriter, r *http.Request) {
+	info := VersionInfo{
+		Version:   version,
+		Commit:    commit,
+		BuildTime: buildTime,
+		GoVersion: runtime.Version(),
+	}
+	writeJSON(w, http.StatusOK, info)
+}
+
 func handleCreateProviderDraft(w http.ResponseWriter, r *http.Request, fn func(context.Context, CreateProviderDraftRequest) (ProviderDraftInfo, error)) {
 	if fn == nil {
 		writeHTTPError(w, &httpError{StatusCode: http.StatusInternalServerError, Code: "server_misconfigured", Message: "create-provider-draft action is not configured"})