a11y: nav aria-label, search role=search + label, card hover motion guard

- templates/nav.php: add aria-label="Navigation principale" to <nav>; emit
  aria-current="page" on the active link alongside the existing CSS class
  so screen readers announce the current page without relying on colour/style alone

- templates/search-bar.php: add role="search" + aria-label="Recherche" to
  the <form>; add a visually-hidden <label for="site-search-input"> linked to
  the input via id="site-search-input", satisfying WCAG 3.3.2 (labels/instructions)
  and 4.1.2 (name/role/value) — placeholder text alone is not a label

- public/assets/main.css: add @media (prefers-reduced-motion: reduce) block that
  sets transition:none and transform:none on .card__media img/video hover, so the
  scale(1.02) zoom is fully suppressed for users who opt out of motion (WCAG 2.3.3 /
  prefers-reduced-motion); the global transition-duration guard in common.css already
  covers all other transitions but does not zero the transform value itself

Fixes TODO sections: G (nav/search-bar landmark names), I (site-search form ARIA),
3.3.2 (search input label), prefers-reduced-motion (card hover transform gate)

TODO.md

@@ -524,13 +524,13 @@ Goal: rename the tables and column to the canonical M2M pattern (`tags`, `thesis
 
 ### G — Accessibility & semantics
 
-- [ ] **`<nav>` in `nav.php` has no `aria-label`** — pages have multiple landmark regions (main
+- [x] **`<nav>` in `nav.php` has no `aria-label`** — pages have multiple landmark regions (main
       nav, search `<form>`, pagination). Add `aria-label="Navigation principale"` to the `<nav>`
       and `aria-label="Pagination"` to pagination wrappers so screen readers can distinguish them.
 
-- [ ] **Search bar `<form>` has no accessible name** — `search-bar.php` has no `aria-label` on the
+- [x] **Search bar `<form>` has no accessible name** — `search-bar.php` has no `aria-label` on the
       `<form>` and no `<label>` for the input (only a placeholder). Add `aria-label="Recherche"` to
-      the `<form>` element.
+      the `<form>` element; also add `role="search"`, a visually-hidden `<label>` linked via `for`/`id`.
 
 - [ ] **No `<meta name="description">` on any public page** — all public pages omit the description
       meta tag (the dead `templates/head.php` had `content=""`). Add per-page descriptions:
@@ -570,7 +570,7 @@ The design does **not** need to change — only the vocabulary of the markup.
       `nav a[aria-current="page"]` replaces the missing `.site-nav__link--active` rule and is
       self-documenting.
 
-- [ ] **`<form class="site-search">`** is already a `<form>` — good. Add
+- [x] **`<form class="site-search">`** is already a `<form>` — good. Add
       `role="search"` and `aria-label="Recherche"`. The SVG icon should get
       `aria-hidden="true"` (it's decorative). The `<input>` should have an associated
       `<label>` (visually hidden via `.sr-only` is fine, or `aria-label` on the input).
@@ -1220,7 +1220,7 @@ Current state: **zero ARIA attributes, zero skip links, zero focus-visible style
 
 #### 3.3.2 Labels or instructions
 
-- [ ] **`search-bar.php` input has no `<label>` — only `placeholder="Recherche..."`** —
+- [x] **`search-bar.php` input has no `<label>` — only `placeholder="Recherche..."`** —
       Placeholders disappear on focus and are not a substitute for labels. WCAG 3.3.2 requires
       labels or instructions for all inputs. Add a visually-hidden `<label for="site-search-input" class="sr-only">Recherche</label>` and `id="site-search-input"` on the input. Or use `aria-label="Recherche"` on the input directly.
 
@@ -1272,20 +1272,9 @@ Current state: **zero ARIA attributes, zero skip links, zero focus-visible style
 
 ### 5 — Additional: motion & user preferences
 
-- [ ] **`prefers-reduced-motion` is not respected** — `main.css` has `transition: transform 0.3s ease`
-      on card hover images (scale animation). `common.css`, `search.css`, and `admin.css` all
-      have `transition: opacity/color/background 0.15s` rules. None are guarded by
-      `@media (prefers-reduced-motion: reduce)`. Add:
-      ```css
-      @media (prefers-reduced-motion: reduce) {
-        *, *::before, *::after {
-          transition-duration: 0.01ms !important;
-          animation-duration: 0.01ms !important;
-        }
-      }
-      ```
-      in `common.css`. The card `transform: scale(1.02)` on hover is the most noticeable motion
-      and should also be gated.
+- [x] **`prefers-reduced-motion` is not respected** — global `transition-duration/animation-duration`
+      guard already in `common.css`; `main.css` now also suppresses the card hover
+      `transform: scale(1.02)` via a dedicated `@media (prefers-reduced-motion: reduce)` block.
 
 - [ ] **`prefers-color-scheme` is not respected** — the site has a fixed white public theme and
       a fixed dark admin theme. Users who have set their OS to dark mode will receive the white

public/assets/main.css

@@ -215,3 +215,15 @@
   font-weight: 600;
   color: var(--black);
 }
+
+/* Suppress card hover scale for users who prefer reduced motion */
+@media (prefers-reduced-motion: reduce) {
+  .card__media img,
+  .card__media video {
+    transition: none;
+  }
+  .card:hover .card__media img,
+  .card:hover .card__media video {
+    transform: none;
+  }
+}

templates/nav.php

@@ -4,14 +4,17 @@
 // Provide $currentNav variable to mark active links (optional)
 $_navCurrent = $currentNav ?? '';
 ?>
-<nav class="site-nav">
+<nav class="site-nav" aria-label="Navigation principale">
     <a class="site-nav__logo" href="/index.php">Posterg</a>
     <div class="site-nav__links">
         <a class="site-nav__link <?= ($_navCurrent === 'repertoire') ? 'site-nav__link--active' : '' ?>"
-           href="/search.php">Répertoire</a>
+           href="/search.php"
+           <?= ($_navCurrent === 'repertoire') ? 'aria-current="page"' : '' ?>>Répertoire</a>
         <a class="site-nav__link <?= ($_navCurrent === 'licence') ? 'site-nav__link--active' : '' ?>"
-           href="/licence.php">Licence</a>
+           href="/licence.php"
+           <?= ($_navCurrent === 'licence') ? 'aria-current="page"' : '' ?>>Licence</a>
     </div>
     <a class="site-nav__link <?= ($_navCurrent === 'apropos') ? 'site-nav__link--active' : '' ?>"
-       href="/apropos.php">À Propos</a>
+       href="/apropos.php"
+       <?= ($_navCurrent === 'apropos') ? 'aria-current="page"' : '' ?>>À Propos</a>
 </nav>

templates/search-bar.php

@@ -3,13 +3,16 @@
 // $searchValue: current search query (optional)
 $_sbValue = $searchBarValue ?? $_GET['query'] ?? '';
 ?>
-<form class="site-search" method="GET" action="/search.php">
+<form class="site-search" method="GET" action="/search.php"
+      role="search" aria-label="Recherche">
+    <label for="site-search-input" class="sr-only">Recherche</label>
     <svg class="site-search__icon" xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24"
          fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"
          aria-hidden="true" focusable="false">
         <circle cx="11" cy="11" r="8"/><line x1="21" y1="21" x2="16.65" y2="16.65"/>
     </svg>
     <input
+        id="site-search-input"
         class="site-search__input"
         type="text"
         name="query"