feat: P7 polls + P8 hashtags

P7 — Опросы в Telegram:
- routes/polls.js: POST /api/channels/:id/poll (sendPoll + schedule support)
- DB: scheduled_posts.post_type + meta для отложенных опросов
- scheduledPostsRunner: обработка post_type='poll' через sendPoll
- index.js: роут /api/channels подключён

P8 — Хештеги:
- ai.js: generateHashtags() через Claude Haiku, JSON-массив тегов
- routes/generate.js: POST /api/generate/hashtags

src/services/scheduledPostsRunner.js

@@ -325,10 +325,26 @@ async function publishOne(scheduledPost) {
     // imgSource === 'none' → photoUrl остаётся null
   }
 
-  if (!text) throw new Error('Empty text and no article');
+  if (!text && scheduledPost.post_type !== 'poll') throw new Error('Empty text and no article');
 
   let messageId;
-  if (channel.platform === 'telegram' || !channel.platform) {
+
+  // Опрос — отдельная ветка
+  if (scheduledPost.post_type === 'poll') {
+    if (channel.platform !== 'telegram') throw new Error('Опросы только в Telegram');
+    const { sendPoll } = require('../routes/polls');
+    const meta = scheduledPost.meta || {};
+    messageId = await sendPoll({
+      channel,
+      question: meta.question || scheduledPost.text,
+      options:  meta.options || [],
+      is_anonymous: meta.is_anonymous ?? true,
+      allows_multiple_answers: meta.allows_multiple_answers ?? false,
+      type: meta.type || 'regular',
+      correct_option_id: meta.correct_option_id,
+      explanation: meta.explanation,
+    });
+  } else if (channel.platform === 'telegram' || !channel.platform) {
     messageId = await publishToTelegram({ channel, text, photoUrl, article });
   } else if (channel.platform === 'vk') {
     messageId = await publishToVK({ channel, text, photoUrl, article });