feat: add maxSyncPeriod configuration to TFS settings

- Introduced maxSyncPeriod option in TfsConfigForm for user-defined synchronization duration.
- Updated TfsService to filter pull requests based on the configured maxSyncPeriod.
- Enhanced TfsPullRequest type to include 'rejected' status for better PR management.
- Set default maxSyncPeriod to '90d' in user preferences and TFS configuration.

src/lib/types.ts

@@ -221,7 +221,7 @@ export interface TfsPullRequest {
   pullRequestId: number;
   title: string;
   description?: string;
-  status: 'active' | 'completed' | 'abandoned';
+  status: 'active' | 'completed' | 'abandoned' | 'rejected';
   createdBy: {
     displayName: string;
     uniqueName: string; // email