修复 geoip/runtime.go 真死代码：ensureServerMMDB 的 os.Stat 错误被 if-init 遮蔽，err != nil && !os.IsNotExist(err) 恒为 false（外层 err 恒 nil），防御检查从未生效；改为显式捕获 statErr，stat 非 not-exist 错误现在正确返回。基准新增第 4 维度 govet nilness+unusedwrite（文档化扩展），当前 0。

Result: {"status":"keep","total_issues":8,"golint_canonicalheader":0,"golint_errname":0,"golint_errorlint":1,"golint_exhaustive":0,"golint_forcetypeassert":0,"golint_gosec":0,"golint_intrange":0,"golint_modernize":3,"golint_nilnil":3,"golint_perfsprint":0,"golint_prealloc":0,"golint_recvcheck":1,"golint_usestdlibvars":0,"golint_wastedassign":0,"golint_total":8,"golint_test_testifylint":0,"golint_test_thelper":0,"golint_test_usetesting":0,"golint_test_total":0,"golint_vetx_total":0,"eslint_problems":0,"eslint_errors":0,"eslint_warnings":0,"tsc_errors":0,"measure_s":37}

internal/apps/openflare/geoip/runtime.go

@@ -91,11 +91,12 @@ func ensureServerMMDB() (string, error) {
 	if err != nil {
 		return "", err
 	}
-	if _, err := os.Stat(path); err == nil {
+	_, statErr := os.Stat(path)
+	if statErr == nil {
 		return path, nil
 	}
-	if err != nil && !os.IsNotExist(err) {
-		return "", err
+	if !os.IsNotExist(statErr) {
+		return "", statErr
 	}
 
 	// Control plane: seed Country from embedded asset (no City; Agent uses disk/image).