fix(a11y): status badges no longer colour-only; fix aria on ✕ buttons (WCAG 1.4.1, 2.5.3)

admin/index.php — status badges (WCAG 1.4.1 Use of Colour):
  - Published badge: prefix ● symbol (aria-hidden) + aria-label="Statut : Publié"
  - Pending badge:   prefix ◌ symbol (aria-hidden) + aria-label="Statut : En attente"
  - Access badges (Libre/Interne/Interdit): prefix ○/◑/● symbol per type (aria-hidden)
    + aria-label="Accès : [type]"; symbol chosen from a PHP map keyed on the slug
  Each badge now communicates its state through shape AND colour, not colour alone.

admin/index.php — ✕ Réinitialiser link (WCAG 2.5.3 / 1.1.1):
  - ✕ wrapped in <span aria-hidden="true"> so the decorative symbol is skipped by
    screen readers; accessible name remains "Réinitialiser"

admin/add.php + admin/edit.php — jury remove buttons (WCAG 2.5.3):
  - All four ✕ remove buttons (2 static template rows + 2 JS-generated innerHTML strings)
    given aria-label="Supprimer ce lecteur"; the bare ✕ Unicode character has no
    speech equivalent so the aria-label replaces rather than supplements the label

TODO.md

@@ -939,7 +939,7 @@ Current state: **zero ARIA attributes, zero skip links, zero focus-visible style
       `search-bar.php` is purely decorative (the `<input>` carries all meaning). Add
       `aria-hidden="true"` and `focusable="false"` to the SVG.
 
-- [ ] **Admin `<nav>` logo is a text link - fine. But "✕ Réinitialiser" and "✕" remove buttons**
+- [x] **Admin `<nav>` logo is a text link - fine. But "✕ Réinitialiser" and "✕" remove buttons**
       use a bare Unicode `✕` as their visible label with no accessible name alternative.
       For the "✕" jury-remove buttons in `add.php`/`edit.php`, add `aria-label="Supprimer ce membre du jury"`.
       For "✕ Réinitialiser" in `index.php`, the text is adequate; the `✕` symbol is decorative
@@ -963,7 +963,7 @@ Current state: **zero ARIA attributes, zero skip links, zero focus-visible style
       because they label a group of checkboxes. These should use `<fieldset>/<legend>` instead
       so the group label is programmatically associated with all its checkboxes.
 
-- [ ] **Status badges in `admin/index.php` convey state by colour alone** - "Publié" (green) /
+- [x] **Status badges in `admin/index.php` convey state by colour alone** - "Publié" (green) /
       "En attente" (yellow) / "Libre" (green) / "Interne" (blue) / "Interdit" (red) all rely
       entirely on colour to distinguish states. This fails **1.4.1 Use of Colour**. Add a
       visible non-colour distinction (e.g. a prefix icon character with `aria-hidden="true"`)
@@ -981,7 +981,7 @@ Current state: **zero ARIA attributes, zero skip links, zero focus-visible style
 
 #### 1.4.1 Use of colour (see also 1.3.1 above)
 
-- [ ] **Admin status badges distinguish states by colour only** - covered above.
+- [x] **Admin status badges distinguish states by colour only** - covered above.
 
 - [ ] **Active nav link has no non-colour indicator** - `.site-nav__link--active` is applied in
       PHP but has no CSS rule at all (flagged in the semantic/CSS audit). Even if a rule existed,
@@ -1165,11 +1165,11 @@ Current state: **zero ARIA attributes, zero skip links, zero focus-visible style
 
 #### 2.5.3 Label in name
 
-- [ ] **`<a class="clear-filter">✕ Réinitialiser</a>`** - the visible label starts with a
+- [x] **`<a class="clear-filter">✕ Réinitialiser</a>`** - the visible label starts with a
       symbol. Fine as long as "Réinitialiser" is in the accessible name, which it is (it's text
       content). No failure here, but the `✕` should be `aria-hidden="true"`.
 
-- [ ] **Admin jury remove buttons `✕`** - the visible label is `✕` only. The accessible name
+- [x] **Admin jury remove buttons `✕`** - the visible label is `✕` only. The accessible name
       must contain (or start with) the visible label text. Since `✕` has no speech equivalent,
       `aria-label="Supprimer ce lecteur"` replaces it entirely, which satisfies 2.5.3.