fix(store): add proper GC with Handler and interval gating

Address maintainer feedback on PR #1239:
- Add Handler: repo.DeleteObject to prevent nil panic in Prune
- Handle ErrLooseObjectsNotSupported gracefully
- Add 5-minute interval gating to avoid repack overhead on every write
- Remove sirupsen/logrus dependency (best-effort silent GC)

Fixes #1104

internal/store/gitstore.go

@@ -21,6 +21,9 @@ import (
 	cliproxyauth "github.com/router-for-me/CLIProxyAPI/v6/sdk/cliproxy/auth"
 )
 
+// gcInterval defines minimum time between garbage collection runs.
+const gcInterval = 5 * time.Minute
+
 // GitTokenStore persists token records and auth metadata using git as the backing storage.
 type GitTokenStore struct {
 	mu        sync.Mutex
@@ -31,6 +34,7 @@ type GitTokenStore struct {
 	remote    string
 	username  string
 	password  string
+	lastGC    time.Time
 }
 
 // NewGitTokenStore creates a token store that saves credentials to disk through the
@@ -613,6 +617,7 @@ func (s *GitTokenStore) commitAndPushLocked(message string, relPaths ...string)
 	} else if errRewrite := s.rewriteHeadAsSingleCommit(repo, headRef.Name(), commitHash, message, signature); errRewrite != nil {
 		return errRewrite
 	}
+	s.maybeRunGC(repo)
 	if err = repo.Push(&git.PushOptions{Auth: s.gitAuth(), Force: true}); err != nil {
 		if errors.Is(err, git.NoErrAlreadyUpToDate) {
 			return nil
@@ -652,6 +657,23 @@ func (s *GitTokenStore) rewriteHeadAsSingleCommit(repo *git.Repository, branch p
 	return nil
 }
 
+func (s *GitTokenStore) maybeRunGC(repo *git.Repository) {
+	now := time.Now()
+	if now.Sub(s.lastGC) < gcInterval {
+		return
+	}
+	s.lastGC = now
+
+	pruneOpts := git.PruneOptions{
+		OnlyObjectsOlderThan: now,
+		Handler:              repo.DeleteObject,
+	}
+	if err := repo.Prune(pruneOpts); err != nil && !errors.Is(err, git.ErrLooseObjectsNotSupported) {
+		return
+	}
+	_ = repo.RepackObjects(&git.RepackConfig{})
+}
+
 // PersistConfig commits and pushes configuration changes to git.
 func (s *GitTokenStore) PersistConfig(_ context.Context) error {
 	if err := s.EnsureRepository(); err != nil {