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/routes/generate.js

@@ -117,6 +117,20 @@ router.get('/image-styles', async (_, res) => {
 });
 
 // POST /api/generate/topics-ideas — синхронные идеи тем для канала
+router.post('/hashtags', async (req, res) => {
+  try {
+    const { channelId, postText, count = 8 } = req.body;
+    const userId = req.headers['x-user-id'] ? parseInt(req.headers['x-user-id']) : null;
+    if (!postText?.trim()) return res.status(400).json({ error: 'postText обязателен' });
+    const channel = channelId ? await channelsSvc.getChannel(channelId, userId) : null;
+    const ai = require('../services/ai');
+    const tags = await ai.generateHashtags(channel, { postText, count });
+    res.json({ hashtags: tags });
+  } catch (err) {
+    res.status(500).json({ error: err.message });
+  }
+});
+
 router.post('/topics-ideas', async (req, res) => {
   try {
     const { channelId, count = 7 } = req.body;