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

src/Database.php

@@ -115,6 +115,30 @@ class Database {
         return $stmt->fetchAll();
     }
 
+    /**
+     * Get theses from the latest published year, in random order (per request).
+     * Used for the default home page view.
+     */
+    public function getLatestYearTheses(int $limit = 24): array {
+        $sql = "SELECT * FROM v_theses_public
+                WHERE year = (SELECT MAX(year) FROM theses WHERE is_published = 1)
+                ORDER BY RANDOM()
+                LIMIT :limit";
+        $stmt = $this->pdo->prepare($sql);
+        $stmt->bindValue(':limit', $limit, PDO::PARAM_INT);
+        $stmt->execute();
+        return $stmt->fetchAll();
+    }
+
+    /**
+     * Get the latest year that has published theses
+     */
+    public function getLatestPublishedYear(): ?int {
+        $stmt = $this->pdo->query("SELECT MAX(year) FROM theses WHERE is_published = 1");
+        $val = $stmt->fetchColumn();
+        return $val ? (int)$val : null;
+    }
+
     /**
      * Count all published theses
      */
@@ -648,6 +672,65 @@ class Database {
         return $result ? $result['id'] : null;
     }
 
+    // ========================================================================
+    // STATIC PAGES METHODS
+    // ========================================================================
+
+    /**
+     * Get a static page by slug
+     * @param string $slug Page slug (e.g. 'about', 'licenses')
+     * @return array|null
+     */
+    public function getPage(string $slug): ?array {
+        $stmt = $this->pdo->prepare("SELECT * FROM pages WHERE slug = ?");
+        $stmt->execute([$slug]);
+        $row = $stmt->fetch();
+        return $row ?: null;
+    }
+
+    /**
+     * Update content for a static page by slug
+     * @throws Exception if slug not found
+     */
+    public function savePage(string $slug, string $content): void {
+        $stmt = $this->pdo->prepare("SELECT id FROM pages WHERE slug = ?");
+        $stmt->execute([$slug]);
+        if (!$stmt->fetch()) {
+            throw new Exception("Page slug not found: $slug");
+        }
+        $stmt = $this->pdo->prepare(
+            "UPDATE pages SET content = ?, updated_at = CURRENT_TIMESTAMP WHERE slug = ?"
+        );
+        $stmt->execute([$content, $slug]);
+    }
+
+    /**
+     * Get all static pages
+     */
+    public function getAllPages(): array {
+        $stmt = $this->pdo->query("SELECT * FROM pages ORDER BY slug");
+        return $stmt->fetchAll();
+    }
+
+    // ========================================================================
+    // LICENSE TYPE METHODS
+    // ========================================================================
+
+    /**
+     * Get all license types ordered by name
+     */
+    public function getLicenseTypes(): array {
+        $stmt = $this->pdo->query("SELECT * FROM license_types ORDER BY name");
+        return $stmt->fetchAll();
+    }
+
+    /**
+     * Alias for form-loading consistency
+     */
+    public function getAllLicenseTypes(): array {
+        return $this->getLicenseTypes();
+    }
+
     /**
      * Insert a thesis file record
      */