Fixes #341065
Fixes #341088

Summary

• allow a Copilot Connector left in a remote pending state after interrupted or cancelled authorization to expose its existing retry path
• preserve deduplication for locally active connection operations
• add focused state/action tests and deterministic pending-connector fixtures backed by the production UI and install service

Validation

• ./scripts/test.sh --reporter dot --run src/vs/workbench/contrib/chat/test/browser/aiCustomization/connectorPresentation.test.ts --run src/vs/workbench/contrib/chat/test/browser/aiCustomization/customizationMarketplaceInstallService.test.ts --run src/vs/workbench/contrib/chat/test/browser/aiCustomization/embeddedMarketplaceDetail.test.ts — passed, 178 tests
• npm run typecheck-client — passed
• changed-file ESLint — passed
• all four dark/light pending-connector fixture variants rendered without fixture errors
• complete production-path UI probe passed:
  • connector detail: Connection pending + Try Again + 0 calls → guarded in-flight retry + 1 call → Connected + Disconnect + 1 call
  • Discover: orphaned remote pending + Connect + 0 calls → busy/disabled Connecting… + 1 call → Disconnect + 1 call

UI evidence

The attached videos are ordered as follows:

1. Before: the pending connector exposes only Unavailable and cannot retry authorization.
2. After: six asserted chapters cover both recovery surfaces:
   • the connector detail exposes Try Again;
   • Try Again is guarded while its single connector call is in flight;
   • the connector reaches Connected/Disconnect;
   • Discover recovers the post-cancel state with Connect;
   • Discover shows busy/disabled Connecting… while its single connector call is in flight;
   • Discover reaches Disconnect without a duplicate call.