wcag: fix 2.4.4 duplicate link text on home page cards

Add <span class="sr-only">, YEAR</span> to each thesis card <p> in
public/index.php. Screen readers now read "Author – Title, 2024" instead
of bare "Author – Title", so two theses sharing the same title produce
distinct accessible names (WCAG 2.4.4 Link Purpose — In Context).

Also audit and close WCAG 2.4.3: the tfe.php back link (<a class="tfe-back-link">
← Retour</a>) is already the first child of <header class="tfe-left">
in DOM order, preceding <h1 class="tfe-title">. No code change needed;
TODO item marked done.

TODO.md

@@ -29,3 +29,6 @@ Pending tasks have been split into topic files under [`todo/`](todo/README.md):
 
 - [x] `admin-submit-wrap` → `admin-form-footer` rename: updated all 6 admin templates (`add.php`, `edit.php`, `login.php`, `account.php`, `import.php`, `pages-edit.php`) and all 8 CSS selectors in `admin.css` (`.admin-form > div:not(…)` exclusion guards, `.admin-login-box` overrides). Closes `todo/01-css-semantic-refactor.md` submit-wrap task.
 - [x] Marked `status-badge.php` partial and WCAG 1.3.1 status-badge items as already-done in `todo/02-php-components.md` and `todo/04-accessibility.md` (partial + CSS were fully implemented; TODO had not been updated)
+
+- [x] `public/index.php` — WCAG 2.4.4: home page cards now append `<span class="sr-only">, YEAR</span>` to each card's `<p>` link text so screen readers get unique link names when two theses share the same title
+- [x] `todo/04-accessibility.md` — WCAG 2.4.3: marked back-link focus-order item as already done (`tfe-back-link` is already the first DOM element in `.tfe-left`, before `<h1>`)