feat: customPrompt piped through full generation chain

- generatePost: customPrompt или channel.ai_style_prompt → добавляется к userPrompt
- routes/generate.js: принимает customPrompt, передаёт в очередь
- workers/generation.js: передаёт customPrompt в generatePost и generateArticle

src/routes/generate.js

@@ -7,7 +7,7 @@ const generationQueue = require('../workers/generation');
 // POST /api/generate — создать задачу генерации
 router.post('/', async (req, res) => {
   try {
-    const { type, topic, channelId, rubric, keywords = [], useCritique = true } = req.body;
+    const { type, topic, channelId, rubric, keywords = [], useCritique = true, customPrompt } = req.body;
     const userId = req.headers['x-user-id'] || null;
 
     if (!type) return res.status(400).json({ error: 'type is required' });
@@ -22,7 +22,7 @@ router.post('/', async (req, res) => {
     );
     const jobId = rows[0].id;
 
-    await generationQueue.add({ jobId, type, topic, channelId, rubric, keywords, useCritique });
+    await generationQueue.add({ jobId, type, topic, channelId, rubric, keywords, useCritique, customPrompt });
 
     res.json({ jobId, status: 'pending' });
   } catch (err) {