feat: dashboard + tutorials modules - stats tiles, tutorial list, reader, completion

edu/api/tutorials.php

@@ -0,0 +1,47 @@
+<?php
+$user_id = require_auth();
+
+// GET /api/tutorials
+if (get_method() === 'GET' && empty($segments[1])) {
+    $stmt = $pdo->prepare("
+        SELECT t.id, t.slug, t.title, t.description, t.duration_min, t.sort_order,
+            COALESCE(tp.completed, false) AS completed, tp.completed_at
+        FROM tutorials t
+        LEFT JOIN tutorial_progress tp ON tp.tutorial_id = t.id AND tp.user_id = :uid
+        ORDER BY t.sort_order
+    ");
+    $stmt->execute([':uid' => $user_id]);
+    json_ok(['tutorials' => $stmt->fetchAll()]);
+}
+
+// GET /api/tutorials/{slug}
+if (get_method() === 'GET' && !empty($segments[1]) && ($segments[2] ?? '') !== 'complete') {
+    $stmt = $pdo->prepare("
+        SELECT t.*, COALESCE(tp.completed, false) AS completed
+        FROM tutorials t
+        LEFT JOIN tutorial_progress tp ON tp.tutorial_id = t.id AND tp.user_id = :uid
+        WHERE t.slug = :slug
+    ");
+    $stmt->execute([':slug' => $segments[1], ':uid' => $user_id]);
+    $tutorial = $stmt->fetch();
+    if (!$tutorial) json_error('Tutorial nicht gefunden', 404);
+    json_ok(['tutorial' => $tutorial]);
+}
+
+// POST /api/tutorials/{slug}/complete
+if (get_method() === 'POST' && !empty($segments[1]) && ($segments[2] ?? '') === 'complete') {
+    $stmt = $pdo->prepare("SELECT id FROM tutorials WHERE slug = :slug");
+    $stmt->execute([':slug' => $segments[1]]);
+    $tutorial = $stmt->fetch();
+    if (!$tutorial) json_error('Tutorial nicht gefunden', 404);
+
+    $stmt = $pdo->prepare("
+        INSERT INTO tutorial_progress (user_id, tutorial_id, completed, completed_at)
+        VALUES (:uid, :tid, true, NOW())
+        ON CONFLICT (user_id, tutorial_id) DO UPDATE SET completed = true, completed_at = NOW()
+    ");
+    $stmt->execute([':uid' => $user_id, ':tid' => $tutorial['id']]);
+    json_ok(['ok' => true]);
+}
+
+json_error('Unbekannter Tutorials-Endpunkt', 404);