refactor: centralize private file writes and tighten config migration coverage

Move duplicated writePrivateFile logic into pkg/utils.WritePrivateFile, reuse it from config and cron, add the glm-4.7 no-provider-keys test, and extend CI with go vet plus race-enabled tests.

.github/workflows/ci.yml

@@ -29,5 +29,8 @@ jobs:
             exit 1
           fi
 
-      - name: Run tests
-        run: go test ./...
+      - name: Run go vet
+        run: go vet ./...
+
+      - name: Run tests (race)
+        run: go test -race ./...

pkg/config/config.go

@@ -7,6 +7,7 @@ import (
 	"sync"
 
 	"github.com/caarlos0/env/v11"
+	"github.com/sipeed/picoclaw/pkg/utils"
 )
 
 type Config struct {
@@ -252,7 +253,7 @@ func SaveConfig(path string, cfg *Config) error {
 		return err
 	}
 
-	return writePrivateFile(path, data)
+	return utils.WritePrivateFile(path, data)
 }
 
 func (c *Config) WorkspacePath() string {
@@ -320,13 +321,6 @@ func expandHome(path string) string {
 	return path
 }
 
-func writePrivateFile(path string, data []byte) error {
-	if err := os.WriteFile(path, data, 0600); err != nil {
-		return err
-	}
-	return os.Chmod(path, 0600)
-}
-
 func normalizeLegacyModelDefaults(cfg *Config) {
 	if cfg == nil {
 		return

pkg/config/config_test.go

@@ -86,3 +86,23 @@ func TestLoadConfigKeepsLegacyGLMModelWhenZhipuConfigured(t *testing.T) {
 		t.Fatalf("model = %q, want %q", cfg.Agents.Defaults.Model, "glm-4.7")
 	}
 }
+
+func TestLoadConfigKeepsLegacyGLMModelWhenNoProviderKeysConfigured(t *testing.T) {
+	path := filepath.Join(t.TempDir(), "config.json")
+	content := `{
+  "agents": { "defaults": { "model": "glm-4.7" } }
+}`
+
+	if err := os.WriteFile(path, []byte(content), 0644); err != nil {
+		t.Fatalf("failed to write config fixture: %v", err)
+	}
+
+	cfg, err := LoadConfig(path)
+	if err != nil {
+		t.Fatalf("LoadConfig failed: %v", err)
+	}
+
+	if cfg.Agents.Defaults.Model != "glm-4.7" {
+		t.Fatalf("model = %q, want %q", cfg.Agents.Defaults.Model, "glm-4.7")
+	}
+}

pkg/cron/service.go

@@ -12,6 +12,7 @@ import (
 	"time"
 
 	"github.com/adhocore/gronx"
+	"github.com/sipeed/picoclaw/pkg/utils"
 )
 
 type CronSchedule struct {
@@ -318,7 +319,7 @@ func (cs *CronService) saveStoreUnsafe() error {
 		return err
 	}
 
-	return writePrivateFile(cs.storePath, data)
+	return utils.WritePrivateFile(cs.storePath, data)
 }
 
 func (cs *CronService) AddJob(name string, schedule CronSchedule, message string, deliver bool, channel, to string) (*CronJob, error) {
@@ -456,10 +457,3 @@ func generateID() string {
 	}
 	return hex.EncodeToString(b)
 }
-
-func writePrivateFile(path string, data []byte) error {
-	if err := os.WriteFile(path, data, 0600); err != nil {
-		return err
-	}
-	return os.Chmod(path, 0600)
-}

pkg/utils/file.go

@@ -0,0 +1,11 @@
+package utils
+
+import "os"
+
+// WritePrivateFile writes data and enforces 0600 permissions for both new and existing files.
+func WritePrivateFile(path string, data []byte) error {
+	if err := os.WriteFile(path, data, 0600); err != nil {
+		return err
+	}
+	return os.Chmod(path, 0600)
+}