feat: 封面生成流水线、执黑先行二号风格扩展、账号配置更新

- 新增 gen-covers 系列脚本（kling/gpt/t2i/batch/direct/final等方案）
- 执黑先行二号添加9种风格提示词目录（梦核/剪纸/水墨/毛毡/硬核线条等）
- 执黑先行添加封面提示词、执黑先行二号更新图片提示词
- product_viral_factory 账号配置扩充并添加 cover_template 参考图
- capcut_assemble/kling-video-generator/oss-upload/poll-utils 细节修复
- CLAUDE.md 更新流程文档

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

accounts/product_viral_factory/account.json

@@ -3,10 +3,10 @@
   "name": "产品宣传片",
   "description": "PPT内容/卖点 → 结构化解析 → 分镜脚本 → 图片提示词 → 生图 → AI视频 → 成片，支持无风格参考图时由产品图自动派生风格",
   "defaultFormat": "9:16",
-  "imageModel": "gemini",
-  "videoModel": "veo3-fast",
+  "imageModel": "gpt-image",
+  "videoModel": "kling",
   "batchSize": 30,
-  "ttsVoice": "",
+  "ttsVoice": "Chinese (Mandarin)_IntellectualGirl",
   "ttsInstruction": "",
   "storyboardPrompt": "prompts/产品分镜.md",
   "imageStylePrompt": "prompts/图片提示词.md",
@@ -14,6 +14,19 @@
   "references": [],
   "referenceMode": "product-as-style",
   "referenceModeNote": "优先使用references中的风格参考图；无风格图时，由产品参考图自动派生光影/构图/背景风格",
+  "cover": {
+    "imageModel": "gpt-image",
+    "style": "产品爆炸流",
+    "styleNote": "产品居中+热带水果四散爆炸，橙金渐变背景，高饱和度。文字居上，白色粗体大字，金色描边",
+    "template": "references/cover_template.png",
+    "channels": ["抖音", "小红书"],
+    "sizes": {
+      "抖音": "1024x1792",
+      "小红书": "1024x1365"
+    },
+    "textRule": "topicA上下两行居中，白色粗体，金色描边",
+    "lockedAt": "2026-06-06"
+  },
   "capcut": {
     "effects": [],
     "filter": "",
@@ -37,17 +50,37 @@
     "defaultBGM": "",
     "transitions": {
       "strategy": "rhythm",
-      "default": { "name": "溶解", "duration": 400000 },
+      "default": {
+        "name": "溶解",
+        "duration": 400000
+      },
       "byPosition": {
-        "hook":    { "name": "闪白", "duration": 100000 },
-        "keypoint": { "name": "闪白", "duration": 150000 },
-        "body":    { "name": "溶解", "duration": 400000 },
-        "closing": { "name": "闪黑", "duration": 300000 }
+        "hook": {
+          "name": "闪白",
+          "duration": 100000
+        },
+        "keypoint": {
+          "name": "闪白",
+          "duration": 150000
+        },
+        "body": {
+          "name": "溶解",
+          "duration": 400000
+        },
+        "closing": {
+          "name": "闪黑",
+          "duration": 300000
+        }
       }
     },
     "kenBurns": {
       "enabled": true,
-      "default": { "startScale": 1.0, "scaleRate": 0.7, "panXRate": 0, "panYRate": 0 }
+      "default": {
+        "startScale": 1.0,
+        "scaleRate": 0.7,
+        "panXRate": 0,
+        "panYRate": 0
+      }
     }
   }
-}
+}