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/workers/generation.js

@@ -15,7 +15,7 @@ const generationQueue = new Queue('generation', {
 });
 
 generationQueue.process(async (job) => {
-  const { jobId, type, topic, channelId, rubric, keywords, useCritique } = job.data;
+  const { jobId, type, topic, channelId, rubric, keywords, useCritique, customPrompt } = job.data;
 
   await query(`UPDATE generation_jobs SET status='processing', updated_at=NOW() WHERE id=$1`, [jobId]);
 
@@ -28,12 +28,12 @@ generationQueue.process(async (job) => {
 
     if (type === 'post') {
       if (!channel) throw new Error('Channel not found for post generation');
-      const r = await ai.generatePost(channel, { topic, rubric, useCritique });
+      const r = await ai.generatePost(channel, { topic, rubric, useCritique, customPrompt });
       resultText = r.content;
       usage = r.usage;
 
     } else if (type === 'article') {
-      const r = await ai.generateArticle(channel || { language: 'ru' }, { topic, keywords });
+      const r = await ai.generateArticle(channel || { language: 'ru' }, { topic, keywords, customPrompt });
       resultText = r.content;
       usage = r.usage;