Harden command palette keyboard behavior and add tests

[Abidoyesimze]

Summary

Command palette needs stronger keyboard coverage for empty results, selection reset, and focus management.

Affected files

• src/components/CommandPalette.tsx

Tasks

• Fix edge cases: empty results, arrow-key wrap, escape to close, focus return.
• Add unit or component tests for keyboard interactions.
• Verify screen reader labels for result count changes.

Acceptance criteria

• Scope is limited to the files listed (or agreed alternatives in the PR).
• Change is verifiable: tests, screenshots, or written QA steps in the PR.
• No behavior regressions in related user flows.
• No new duplicate abstractions without a one-line rationale in the PR.

Suggested labels

cleanup, a11y, testing

Notes

Standalone cleanup issue from CLEANUP_ISSUES_2026-05.md. Complements the audit queue and product backlog.