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

edu/api/dashboard.php

@@ -0,0 +1,40 @@
+<?php
+$user_id = require_auth();
+if (get_method() !== 'GET') json_error('Methode nicht erlaubt', 405);
+
+$stmt = $pdo->prepare("SELECT COUNT(*) FROM card_progress WHERE user_id = :uid AND last_reviewed_at IS NOT NULL");
+$stmt->execute([':uid' => $user_id]);
+$cards_learned = (int) $stmt->fetchColumn();
+
+$stmt = $pdo->prepare("SELECT COUNT(*) FROM card_progress WHERE user_id = :uid AND next_review <= CURRENT_DATE");
+$stmt->execute([':uid' => $user_id]);
+$cards_due = (int) $stmt->fetchColumn();
+
+$stmt = $pdo->prepare("
+    SELECT COUNT(*) FILTER (WHERE last_rating IN ('easy','medium')) AS correct, COUNT(*) AS total
+    FROM card_progress WHERE user_id = :uid AND last_reviewed_at IS NOT NULL
+");
+$stmt->execute([':uid' => $user_id]);
+$acc = $stmt->fetch();
+$correct_pct = ($acc['total'] > 0) ? round(($acc['correct'] / $acc['total']) * 100) : 0;
+
+$total_cards = (int) $pdo->query("SELECT COUNT(*) FROM cards")->fetchColumn();
+
+$stmt = $pdo->prepare("SELECT COUNT(*) FROM tutorial_progress WHERE user_id = :uid AND completed = true");
+$stmt->execute([':uid' => $user_id]);
+$tutorials_done = (int) $stmt->fetchColumn();
+$tutorials_total = (int) $pdo->query("SELECT COUNT(*) FROM tutorials")->fetchColumn();
+
+$deck_count = (int) $pdo->query("SELECT COUNT(*) FROM decks")->fetchColumn();
+$cheatsheet_count = (int) $pdo->query("SELECT COUNT(*) FROM cheatsheets")->fetchColumn();
+
+$stmt = $pdo->prepare("SELECT score_percent FROM quiz_results WHERE user_id = :uid ORDER BY created_at DESC LIMIT 1");
+$stmt->execute([':uid' => $user_id]);
+$last_quiz = $stmt->fetchColumn();
+
+json_ok([
+    'cards_learned' => $cards_learned, 'cards_due' => $cards_due, 'cards_total' => $total_cards,
+    'correct_pct' => $correct_pct, 'tutorials_done' => $tutorials_done, 'tutorials_total' => $tutorials_total,
+    'deck_count' => $deck_count, 'cheatsheet_count' => $cheatsheet_count,
+    'last_quiz_score' => $last_quiz !== false ? (int) $last_quiz : null
+]);

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);