feat: error logs API

routes/admin.js: GET /logs — объединённые ошибки из 3 источников:
  generation_jobs (status=failed), ai_usage (!succeeded), scheduled_posts (status=failed)
  Сортировка по времени, топ-5 частых ошибок, группировка по типу

src/routes/admin.js

@@ -326,3 +326,82 @@ router.delete('/queue/stuck', async (req, res) => {
     res.json({ ok: true, cleared: rows.length });
   } catch (err) { res.status(500).json({ error: err.message }); }
 });
+
+// ── ERROR LOGS ───────────────────────────────────────────────
+
+// GET /api/admin/logs — последние ошибки из всех источников
+router.get('/logs', async (req, res) => {
+  if (!await requireAdmin(req, res)) return;
+  const limit = Math.min(parseInt(req.query.limit || 50), 200);
+  try {
+    const [genFailed, aiErrors, scheduledFailed] = await Promise.all([
+      // Ошибки генерации
+      query(`
+        SELECT
+          'generation' as source,
+          j.id::text as entity_id,
+          j.type as operation,
+          j.error as message,
+          j.topic as context,
+          u.email as user_email,
+          j.created_at
+        FROM generation_jobs j
+        LEFT JOIN users u ON u.id = j.user_id
+        WHERE j.status = 'failed' AND j.error IS NOT NULL
+        ORDER BY j.created_at DESC LIMIT $1
+      `, [limit]),
+
+      // Ошибки AI провайдеров
+      query(`
+        SELECT
+          'ai_provider' as source,
+          id::text as entity_id,
+          (provider || '/' || request_type) as operation,
+          error_message as message,
+          left(model, 60) as context,
+          NULL as user_email,
+          created_at
+        FROM ai_usage
+        WHERE NOT succeeded AND error_message IS NOT NULL
+        ORDER BY created_at DESC LIMIT $1
+      `, [limit]),
+
+      // Ошибки публикации постов
+      query(`
+        SELECT
+          'publish' as source,
+          sp.id::text as entity_id,
+          (c.platform || ' publish') as operation,
+          'Failed scheduled post' as message,
+          left(sp.custom_text, 60) as context,
+          NULL as user_email,
+          sp.scheduled_at as created_at
+        FROM scheduled_posts sp
+        JOIN channels c ON c.id = sp.channel_id
+        WHERE sp.status = 'failed'
+        ORDER BY sp.scheduled_at DESC LIMIT 20
+      `),
+    ]);
+
+    // Объединяем и сортируем
+    const all = [
+      ...genFailed.rows,
+      ...aiErrors.rows,
+      ...scheduledFailed.rows,
+    ].sort((a, b) => new Date(b.created_at) - new Date(a.created_at))
+     .slice(0, limit);
+
+    // Группируем по типу ошибки для статистики
+    const errorGroups = {};
+    for (const e of all) {
+      const key = e.message?.split('\n')[0]?.slice(0, 80) || 'unknown';
+      errorGroups[key] = (errorGroups[key] || 0) + 1;
+    }
+    const topErrors = Object.entries(errorGroups)
+      .sort((a, b) => b[1] - a[1])
+      .slice(0, 5)
+      .map(([msg, cnt]) => ({ msg, cnt }));
+
+    res.json({ errors: all, total: all.length, topErrors });
+  } catch (err) { res.status(500).json({ error: err.message }); }
+});