Feat/events page loading state

[Unclebaffa]

Below is a summary of the accomplishments:

Key Changes

1. Events Page (src/app/events/page.tsx):

   • Replaced the bare {loading && !error && <p>Loading…</p>} paragraph with the shared Spinner primitive.
   • Wrapped it in an accessible container with role="status" and aria-busy="true" to ensure screen readers are notified of the busy/fetching state.

2. Automated Tests (src/app/events/page.test.tsx):

   • Added comprehensive tests for loading spinner states (initial slow fetch, error, and background auto-refresh).
   • Confirmed that the spinner does not flash or re-appear during background updates.
   • Verified that all 11 tests pass successfully.

3. Documentation (README.md):

   • Added a new subsection under Accessibility documenting the events page loading state and its assistive technology annotations.

4. Commits & Validation:

   • Completed all work in 3 distinct, clean commits on the branch.
   • TypeScript checks and production builds passed cleanly.

Please review the complete walkthrough in the walkthrough.md artifact.

Closes #141