feat: stream MCP probe progress

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

src/main/persistence/workspaceRepository.ts

@@ -123,8 +123,9 @@ export class WorkspaceRepository {
   }
 
   async save(workspace: WorkspaceState): Promise<void> {
+    const { mcpProbingServerIds: _mcpProbingServerIds, ...persistedWorkspace } = workspace;
     await writeJsonFile(this.filePath, {
-      ...workspace,
+      ...persistedWorkspace,
       lastUpdatedAt: nowIso(),
     });
   }