fix: cover images — simplified coherent prompts, no style conflicts

Проблема: VISUAL CONCEPT и STYLE из COVER_STYLES противоречили друг другу
  (sculptor on marble + frosted glass style = модель рисовала свой дефолт)

Решение: 3 простых параметра на статью без конфликтов:
  SUBJECT: что изображено (из getVisualMetaphor)
  SETTING: антураж (12 вариантов по articleId % 12):
    oak desk | marble | slate | workbench | velvet | dawn mist |
    terracotta | city night | concrete | library | frost | brick
  LIGHTING: конкретный свет (golden hour, studio, rim light, etc.)
  COLOR TEMPERATURE: warm amber / cool whites / etc.

Убраны STYLE/PALETTE/MOOD/COMPOSITION блоки которые путали модель.
Теперь каждая статья = уникальная физическая сцена с конкретным светом.

src/services/covers.js

@@ -167,20 +167,47 @@ function buildCoverPrompt({ title, tags = [], articleId = 0, channelStyle = null
     paletteDesc = PALETTES[channelStyle.image_palette] || null;
   }
 
-  const visualMetaphor = getVisualMetaphor(title, tags, articleId);
+  // Выбираем сцену — конкретное место + свет + цвет
+  // Привязаны к articleId чтобы каждая статья имела уникальный антураж
+  const SCENES = [
+    { setting: 'warm oak desktop surface, afternoon sunlight through window from left casting long shadows',
+      lighting: 'golden hour, soft shadows', temp: 'warm amber tones' },
+    { setting: 'white marble surface, clean studio setup, diffused overhead light',
+      lighting: 'flat professional studio lighting', temp: 'cool whites and greys' },
+    { setting: 'dark slate table, single focused spotlight from above',
+      lighting: 'dramatic single point light, deep shadows', temp: 'high contrast, near-monochrome' },
+    { setting: 'weathered wooden workbench outdoors, overcast daylight',
+      lighting: 'soft even overcast light, no harsh shadows', temp: 'muted natural greens and browns' },
+    { setting: 'black velvet surface in studio, rim lighting from behind',
+      lighting: 'rim lit, glowing edges, dark center', temp: 'rich blacks with gold highlights' },
+    { setting: 'blue morning mist, outdoor scene at dawn, dew on surfaces',
+      lighting: 'early morning blue hour, soft mist', temp: 'cool blues and pale greys' },
+    { setting: 'terracotta-tiled floor, Mediterranean afternoon, dappled shade',
+      lighting: 'dappled sunlight through leaves', temp: 'warm sienna and ochre tones' },
+    { setting: 'glass surface over city lights at night, reflections below',
+      lighting: 'city glow from below, urban night', temp: 'multicolored bokeh, deep navy' },
+    { setting: 'rough concrete surface, industrial warehouse, fluorescent light',
+      lighting: 'harsh overhead fluorescent, cool and flat', temp: 'grey concrete tones, accent cyan' },
+    { setting: 'antique wooden library floor, surrounded by stacked books, candlelight',
+      lighting: 'warm candlelight from one side', temp: 'deep amber and aged parchment' },
+    { setting: 'frosted glass surface, winter morning, ice crystals at edges',
+      lighting: 'diffused winter morning light', temp: 'icy blues and whites' },
+    { setting: 'warm brick wall background, artisan workshop, window light',
+      lighting: 'soft side window light', temp: 'warm brick reds and natural wood' },
+  ];
+  const scene = SCENES[articleId % SCENES.length];
+  const visualConcept = getVisualMetaphor(title, tags, articleId);
 
-  return `Create a wide 16:9 editorial cover illustration.
+  return `Generate a 16:9 editorial cover photograph or illustration.
 
-VISUAL CONCEPT: ${visualMetaphor}
+SUBJECT: ${visualConcept}
+SETTING: ${scene.setting}
+LIGHTING: ${scene.lighting}
+COLOR TEMPERATURE: ${scene.temp}
+${tagHint ? `THEMATIC CONTEXT: ${tagHint}` : ''}
+${channelStyle?.image_prompt_instructions ? `CHANNEL STYLE: ${channelStyle.image_prompt_instructions}` : ''}
 
-STYLE: ${styleDesc}.
-${paletteDesc ? `COLOR PALETTE: ${paletteDesc}.` : ''}
-MOOD: ${moodDesc}.
-COMPOSITION: ${compositionDesc}
-${tagHint ? `THEME (abstract cues only): ${tagHint}.` : ''}
-${channelStyle?.image_prompt_instructions ? `\nCHANNEL STYLE: ${channelStyle.image_prompt_instructions}` : ''}
-
-RULE: absolutely no text, no letters, no words, no logos, no real human faces.`;
+RULES: photorealistic or illustrated — either works. NO text, NO letters, NO logos, NO human faces.`;
 }
 
 /**