feat(auth): add skip persistence context key for file watcher events

Introduce `WithSkipPersist` to disable persistence during Manager Update/Register calls, preventing write-back loops caused by redundant file writes. Add corresponding tests and integrate with existing file store and conductor logic.

sdk/cliproxy/auth/conductor.go

@@ -1642,6 +1642,9 @@ func (m *Manager) persist(ctx context.Context, auth *Auth) error {
 	if m.store == nil || auth == nil {
 		return nil
 	}
+	if shouldSkipPersist(ctx) {
+		return nil
+	}
 	if auth.Attributes != nil {
 		if v := strings.ToLower(strings.TrimSpace(auth.Attributes["runtime_only"])); v == "true" {
 			return nil