feat: Nyxos Plus as primary image provider, aiguoguo as fallback

- app_settings: AI_IMAGE_BASE_URL → https://plus.nyxos.workers.dev/v1
- app_settings: AI_IMAGE_FALLBACK_BASE_URL/API_KEY → aiguoguo (резерв)
- config/index.js: загружает imageFallbackBaseUrl + imageFallbackApiKey
- covers.js: generateCoverViaImageGenerations пробует Nyxos, при 5xx/timeout
  автоматически переключается на aiguoguo

src/config/index.js

@@ -66,9 +66,11 @@ async function reloadAi() {
 
   config.ai.baseUrl     = pick('AI_TEXT_BASE_URL',  'AI_BASE_URL',       'https://aiprimetech.io/v1');
   config.ai.apiKey      = pick('AI_TEXT_API_KEY',   'AI_API_KEY',        null);
-  config.ai.imageBaseUrl= pick('AI_IMAGE_BASE_URL', 'AI_IMAGE_BASE_URL', 'https://api.aiguoguo199.com/v1');
+  config.ai.imageBaseUrl= pick('AI_IMAGE_BASE_URL', 'AI_IMAGE_BASE_URL', 'https://plus.nyxos.workers.dev/v1');
   config.ai.imageApiKey = pick('AI_IMAGE_API_KEY',  'AI_IMAGE_API_KEY',  config.ai.apiKey);
-  config.ai.imageModel  = pick('AI_IMAGE_MODEL',    'AI_MODEL_IMAGE',    'gpt-image-1-mini');
+  config.ai.imageFallbackBaseUrl = (s['AI_IMAGE_FALLBACK_BASE_URL'] && s['AI_IMAGE_FALLBACK_BASE_URL'].trim()) || 'https://api.aiguoguo199.com/v1';
+  config.ai.imageFallbackApiKey  = (s['AI_IMAGE_FALLBACK_API_KEY']  && s['AI_IMAGE_FALLBACK_API_KEY'].trim())  || config.ai.imageApiKey;
+  config.ai.imageModel  = pick('AI_IMAGE_MODEL',    'AI_MODEL_IMAGE',    'gpt-image-2');
   config.ai.imageModelViaResponses = pick('AI_IMAGE_MODEL_VIA_RESPONSES', 'AI_MODEL_IMAGE_VIA_RESPONSES', 'gpt-5.5');
   config.ai.models.post    = pick('AI_TEXT_MODEL_POST',    'AI_MODEL_POST',    'claude-haiku-4-5-20251001');
   config.ai.models.article = pick('AI_TEXT_MODEL_ARTICLE', 'AI_MODEL_ARTICLE', 'claude-sonnet-4-6');

src/services/covers.js

@@ -266,56 +266,42 @@ async function generateCoverViaImagesEndpoint({ prompt }) {
  * Более стабильный чем /responses, поддерживает gpt-image-1-mini/gpt-image-2.
  */
 async function generateCoverViaImageGenerations({ prompt }) {
-  const model = config.ai.imageModel || 'gpt-image-1-mini';
+  const model = config.ai.imageModel || 'gpt-image-2';
-  const baseUrl = config.ai.imageBaseUrl || config.ai.baseUrl;
+
-  const started = Date.now();
+  async function tryProvider(baseUrl, apiKey) {
-  let res;
+    const started = Date.now();
-  try {
+    try {
-    res = await axios.post(
+      const res = await axios.post(
-      `${baseUrl}/images/generations`,
+        `${baseUrl}/images/generations`,
-      {
+        { model, prompt: prompt.slice(0, 4000), n: 1, size: '1024x1024', response_format: 'url' },
-        model,
+        { headers: { Authorization: `Bearer ${apiKey}` }, timeout: 120_000 }
-        prompt: prompt.slice(0, 4000),
+      );
-        n: 1,
+      const item = res.data?.data?.[0];
-        size: '1024x1024',
+      if (!item) throw new Error('No image data in response');
-        response_format: 'url', // рекомендовано провайдером: url быстрее чем b64 (~5MB)
+      aiUsage.log({ provider: aiUsage.providerFromBaseUrl(baseUrl), requestType: 'image', model, imageCount: 1, durationMs: Date.now()-started, succeeded: true }).catch(() => {});
-      },
+      if (item.url) {
-      {
+        const r = await axios.get(item.url, { responseType: 'arraybuffer', timeout: 60_000 });
-        headers: { Authorization: `Bearer ${config.ai.imageApiKey}` },
+        return { bytes: Buffer.from(r.data), format: 'png' };
-        timeout: 120_000,
       }
-    );
+      if (item.b64_json) return { bytes: Buffer.from(item.b64_json, 'base64'), format: 'png' };
+      throw new Error('No url or b64_json in response');
+    } catch (err) {
+      aiUsage.log({ provider: aiUsage.providerFromBaseUrl(baseUrl), requestType: 'image', model, imageCount: 1, durationMs: Date.now()-started, succeeded: false, errorMessage: (err.response?.data?.error?.message || err.message || '').slice(0, 500) }).catch(() => {});
+      throw err;
+    }
+  }
+
+  // Основной: Nyxos Plus
+  try {
+    return await tryProvider(config.ai.imageBaseUrl, config.ai.imageApiKey);
   } catch (err) {
-    aiUsage.log({
+    const status = err.response?.status;
-      provider: aiUsage.providerFromBaseUrl(baseUrl),
+    if (!status || status >= 500) {
-      requestType: 'image', model, imageCount: 1,
+      console.warn(`[Cover] primary failed (${status||'timeout'}), trying fallback aiguoguo...`);
-      durationMs: Date.now() - started, succeeded: false,
+      return await tryProvider(config.ai.imageFallbackBaseUrl, config.ai.imageFallbackApiKey);
-      errorMessage: (err.response?.data?.error?.message || err.message || '').slice(0, 500),
+    }
-    }).catch(() => {});
     throw err;
   }
-  const item = res.data?.data?.[0];
-  if (!item) {
-    aiUsage.log({
-      provider: aiUsage.providerFromBaseUrl(baseUrl),
-      requestType: 'image', model, imageCount: 1,
-      durationMs: Date.now() - started, succeeded: false,
-      errorMessage: 'No image data in response',
-    }).catch(() => {});
-    throw new Error('No image data in response');
-  }
-  aiUsage.log({
-    provider: aiUsage.providerFromBaseUrl(baseUrl),
-    requestType: 'image', model, imageCount: 1,
-    durationMs: Date.now() - started, succeeded: true,
-  }).catch(() => {});
-  // Приоритет: url (быстро) → b64_json (fallback для старых моделей)
-  if (item.url) {
-    const r = await axios.get(item.url, { responseType: 'arraybuffer', timeout: 60_000 });
-    return { bytes: Buffer.from(r.data), format: 'png' };
-  }
-  if (item.b64_json) return { bytes: Buffer.from(item.b64_json, 'base64'), format: 'png' };
-  throw new Error('No url or b64_json in response');
 }
 
 /**