feat: licence page, admin pages editor, license types, gradient card placeholders, latest-year home view

- Feature 1: public /licence.php fetches 'licenses' page from DB, renders Markdown
- Feature 1: nav.php adds 'Licence' link with active state
- Feature 2: Database::getPage(), savePage(), getAllPages() methods
- Feature 2: bundled src/Parsedown.php (MIT, zero-dependency)
- Feature 2: apropos.php now renders 'about' page content from DB via Parsedown
- Feature 2: admin/pages.php (list) + admin/pages-edit.php (EasyMDE editor)
- Feature 2: admin/actions/page.php (auth+CSRF+validation+save)
- Feature 2: admin/head.php adds 'Pages statiques' nav link
- Feature 3: storage/schema.sql seeds 8 CC license types
- Feature 3: storage/migrations/003_seed_license_types.sql (applied to live DB)
- Feature 3: Database::getLicenseTypes() / getAllLicenseTypes()
- Feature 3: admin/add.php + formulaire.php: license_id field on add form
- Feature 3: admin/edit.php: license_id field on edit form with raw FK lookup
- Feature 3: tfe.php: shows 'Licence :' meta row when non-null
- Feature 6: main.css: .card__media--gradient styles
- Feature 6: index.php: deterministic HSL gradient placeholder cards
- Feature 6: Database::getLatestYearTheses() + getLatestPublishedYear()
- Feature 6: index.php default home = random latest-year theses with info label

public/admin/edit.php

@@ -36,6 +36,8 @@ try {
             $db->beginTransaction();
 
             // Update thesis basic info
+            $editLicenseId = filter_var($_POST['license_id'] ?? '', FILTER_VALIDATE_INT) ?: null;
+
             $stmt = $pdo->prepare("
                 UPDATE theses SET
                     title = ?,
@@ -47,6 +49,7 @@ try {
                     synopsis = ?,
                     file_size_info = ?,
                     baiu_link = ?,
+                    license_id = ?,
                     is_published = ?,
                     updated_at = CURRENT_TIMESTAMP
                 WHERE id = ?
@@ -62,6 +65,7 @@ try {
                 trim($_POST['synopsis']),
                 !empty($_POST['duration_info']) ? trim($_POST['duration_info']) : null,
                 !empty($_POST['lien']) ? trim($_POST['lien']) : null,
+                $editLicenseId,
                 isset($_POST['is_published']) ? 1 : 0,
                 $thesisId
             ]);
@@ -164,7 +168,13 @@ try {
     $finalityTypes = $db->getAllFinalityTypes();
     $languages = $db->getAllLanguages();
     $formatTypes = $db->getAllFormatTypes();
-    
+    $licenseTypes = $db->getAllLicenseTypes();
+
+    // Fetch raw license_id FK (view only exposes license_type name string)
+    $licenseStmt = $pdo->prepare("SELECT license_id FROM theses WHERE id = ?");
+    $licenseStmt->execute([$thesisId]);
+    $currentLicenseId = $licenseStmt->fetchColumn();
+
     // Set page title for header
     $pageTitle = "Éditer TFE - " . htmlspecialchars($thesis['title']);
 
@@ -247,6 +257,19 @@ try {
                    value="<?= htmlspecialchars($thesis['supervisors'] ?? '') ?>">
         </div>
 
+        <div class="admin-form-row">
+            <label class="admin-label" for="license_id">Licence :</label>
+            <select class="admin-select" id="license_id" name="license_id">
+                <option value="">— Inconnue —</option>
+                <?php foreach ($licenseTypes as $lt): ?>
+                    <option value="<?= $lt['id'] ?>"
+                        <?= ($currentLicenseId == $lt['id']) ? 'selected' : '' ?>>
+                        <?= htmlspecialchars($lt['name']) ?>
+                    </option>
+                <?php endforeach; ?>
+            </select>
+        </div>
+
         <div class="admin-form-row">
             <label class="admin-label" for="titre">Titre :</label>
             <input class="admin-input" type="text" id="titre" name="titre"