fix(desktop): isolate MCP catalog refresh by project

[imshunsuke]

Description

Fix a project-switch race in the Desktop MCP catalog. If a probe or mutation started in project A finished after the user switched to project B, its captured refresh could increment the shared generation and invalidate the in-flight B load. The UI then remained in a loading state with no B catalog.

The hook now records the active catalog owner and ignores refreshes captured by an inactive project before they can mutate shared state.

Related Issues

No matching open issue or PR was found.

Changes Made

• guard catalog loads with the currently active project key
• clear ownership during effect cleanup
• add a deferred-promise hook regression test for the A-to-B race

Checklist

• Changes tested locally
• Code reviewed
• Documentation updated (not necessary; behavior-only bug fix)
• Unit tests added

Validation

Using Node v22.23.2:

• Desktop test suite: 31 files, 195 tests passed
• npm run typecheck
• npm run lint with zero warnings
• npm run build
• uvx pre-commit run --all-files
• git diff --check

[Zongwei9888]

Merged on 2026-09-03 as 5dfa89c. The deferred-promise regression test for the A-to-B switch was what made this easy to verify (typecheck, lint and all 195 Desktop tests green on the merged tree). Ten lines of fix, a real race, a test that pins it — this is the ideal shape for a contribution. Thank you, and welcome.