refactor: single image provider — routerai gpt-5-image-mini only

- config: убраны imageBaseUrl/imageFallbackBaseUrl/imageModel (старые провайдеры)
  Остались только routeraiBaseUrl, routeraiApiKey, routeraiModel
- covers.js: единственная цепочка routerai→retry→local SVG
  Убраны generateCoverViaImageGenerations, ViaResponses (aiprimetech), ViaImagesEndpoint
  generateCoverViaRouterAI: убран quality параметр (routerai игнорирует)
- postImages.js: убраны Nyxos/Aiguoguo, убраны isHD/imgQuality/tryNyxos
- aiUsage.js: реальные цены из статистики routerai.ru:
  gpt-5-image-mini ~₽2.72, всегда 4175 image tokens (high quality)
- index.js: лог показывает routerai вместо старого aiguoguo

src/services/postImages.js

@@ -85,62 +85,38 @@ ${style.image_prompt_instructions ? `\nChannel visual guidelines: ${style.image_
 Composition: 16:9 wide format, balanced, suitable for social media.
 Strictly: no text, no letters, no logos, no faces of real people.`;
 
-  // RouterAI /responses (primary) → Nyxos /images/generations (fallback)
-  // standard: gpt-5-image-mini + low quality (₽0.20/картинка)
-  // hd:       gpt-5.4-image-2  + medium quality (₽2.96/картинка) — для текста на картинках
-  const isHD = channel.image_quality === 'hd';
-  const model = isHD
-    ? 'openai/gpt-5.4-image-2'
-    : (config.ai.routeraiImageModel || 'openai/gpt-5-image-mini');
-  const imgQuality = isHD ? 'medium' : 'low';
+  // Единственный провайдер: routerai /responses + gpt-5-image-mini
+  // Цена: ~₽2.72/картинка. quality параметр не работает, всегда high.
+  const model = config.ai.routeraiModel || 'openai/gpt-5-image-mini';
 
-  async function tryRouterAI() {
+  async function generateViaRouterAI() {
     const started = Date.now();
     try {
       const res = await axios.post(`${config.ai.routeraiBaseUrl}/responses`, {
         model,
         input: `Use the image_generation tool to create this illustration. Only call the tool, no text.\n\n${prompt.slice(0, 3000)}`,
-        tools: [{ type: 'image_generation', quality: imgQuality }],
+        tools: [{ type: 'image_generation' }],
         tool_choice: { type: 'image_generation' },
       }, { headers: { Authorization: `Bearer ${config.ai.routeraiApiKey}` }, timeout: 120_000 });
       const imgCall = (res.data?.output || []).find(o => o.type === 'image_generation_call');
       if (!imgCall?.result) throw new Error('No image in RouterAI response');
-      aiUsage.log({ provider: 'routerai', requestType: 'image_via_responses', model, quality: imgQuality, imageCount: 1, meta: { channel_id: channel.id }, durationMs: Date.now()-started, succeeded: true }).catch(() => {});
+      aiUsage.log({ provider: 'routerai', requestType: 'image_via_responses', model, imageCount: 1, meta: { channel_id: channel.id }, durationMs: Date.now()-started, succeeded: true }).catch(() => {});
       return Buffer.from(imgCall.result, 'base64');
     } catch (err) {
-      aiUsage.log({ provider: 'routerai', requestType: 'image_via_responses', model, quality: imgQuality, imageCount: 1, meta: { channel_id: channel.id }, durationMs: Date.now()-started, succeeded: false, errorMessage: (err.response?.data?.error?.message || err.message || '').slice(0, 500) }).catch(() => {});
-      throw err;
-    }
-  }
-
-  async function tryNyxos() {
-    const m = config.ai.imageModel || 'gpt-image-2';
-    const started = Date.now();
-    try {
-      const res = await axios.post(`${config.ai.imageFallbackBaseUrl}/images/generations`,
-        { model: m, prompt: prompt.slice(0, 4000), n: 1, size: '1024x1024', response_format: 'url' },
-        { headers: { Authorization: `Bearer ${config.ai.imageFallbackApiKey}` }, timeout: 90_000 }
-      );
-      const item = res.data?.data?.[0];
-      if (!item) throw new Error('No image data');
-      aiUsage.log({ provider: 'nyxos', requestType: 'image', model: m, imageCount: 1, meta: { channel_id: channel.id }, succeeded: true }).catch(() => {});
-      if (item.url) { const r = await axios.get(item.url, { responseType: 'arraybuffer', timeout: 60_000 }); return Buffer.from(r.data); }
-      if (item.b64_json) return Buffer.from(item.b64_json, 'base64');
-      throw new Error('No url or b64_json');
-    } catch (err) {
-      aiUsage.log({ provider: 'nyxos', requestType: 'image', model: m, imageCount: 1, meta: { channel_id: channel.id }, succeeded: false, errorMessage: (err.response?.data?.error?.message || err.message || '').slice(0, 500) }).catch(() => {});
+      aiUsage.log({ provider: 'routerai', requestType: 'image_via_responses', model, imageCount: 1, meta: { channel_id: channel.id }, durationMs: Date.now()-started, succeeded: false, errorMessage: (err.response?.data?.error?.message || err.message || '').slice(0, 500) }).catch(() => {});
       throw err;
     }
   }
 
   let bytes;
   try {
-    bytes = await tryRouterAI();
+    bytes = await generateViaRouterAI();
   } catch (err) {
     const status = err.response?.status;
-    if (!status || status >= 500) {
-      console.warn('[postImages] RouterAI failed, trying Nyxos fallback...');
-      bytes = await tryNyxos();
+    if (!status || (status >= 500 && status < 600)) {
+      console.warn(`[postImages] routerai attempt 1 failed (${status||'timeout'}), retry in 10s...`);
+      await new Promise(r => setTimeout(r, 10_000));
+      bytes = await generateViaRouterAI(); // бросит если снова упадёт
     } else { throw err; }
   }