fix(desktop): retry profile model refresh

[tt-a1i]

Summary

• retry forced profile-default model refreshes when the desktop backend is briefly unavailable
• ignore stale refresh results so rapid profile switches cannot clobber the current model pill
• add regression coverage for transient failures and latest-refresh-wins ordering

Fixes #47524

Tests

• npm --workspace apps/desktop run test:ui -- src/app/session/hooks/use-model-controls.test.tsx
• npm --workspace apps/desktop run typecheck

[alt-glitch]

Duplicate of #47537 — both retry the forced profile model refresh on transient backend unavailability and ignore stale refresh results (use-model-controls.ts) for #47524, same approach. #47537 was opened earlier. Consolidating on #47537.

[tt-a1i]

Closing as duplicate of #47537 per maintainer comment. Thanks for the review.