feat: 生成图片提示词agent结构封装

api/app/tasks/memoir_tasks.py

@@ -42,6 +42,7 @@ from app.features.memoir.memoir_images.parser import (
 )
 import hashlib
 from app.core.dependencies import get_image_generator
+from app.agents.image_prompt import ImagePromptOrchestrator
 from app.features.memoir.memoir_images.prompting import MemoirImagePromptService
 from app.features.memoir.memoir_images.schema import (
     completed_image_assets,
@@ -883,7 +884,7 @@ def generate_chapter_images(self, chapter_id: str):
                 logger.info("章节补图跳过: chapter=%s, reason=locked", chapter_id)
                 return {"status": "locked"}
 
-            prompt_service = MemoirImagePromptService(_get_llm(), settings)
+            prompt_orchestrator = ImagePromptOrchestrator(_get_llm(), settings)
             image_generator = get_image_generator()
             storage = TencentCosStorageService.from_env()
             logger.info(
@@ -922,7 +923,7 @@ def generate_chapter_images(self, chapter_id: str):
                     sections_ordered = sorted(sections, key=lambda s: getattr(s, "order_index", 0))
                     first_content = (sections_ordered[0].content or "").strip() if sections_ordered else ""
                     context_excerpt = " ".join(first_content.split("\n")[:5])[:200]
-                    prompt_data = prompt_service.build_cover_prompt(
+                    prompt_data = prompt_orchestrator.build_cover_prompt(
                         chapter_title=chapter.title,
                         chapter_category=chapter.category or "",
                         context_excerpt=context_excerpt,
@@ -985,7 +986,7 @@ def generate_chapter_images(self, chapter_id: str):
                 try:
                     context_lines = (section.content or "").strip().split("\n")[:5]
                     context_excerpt = " ".join(context_lines)[:200]
-                    prompt_data = prompt_service.build_prompt(
+                    prompt_data = prompt_orchestrator.build_prompt(
                         chapter_title=chapter.title,
                         chapter_category=chapter.category or "",
                         description=current_item.get("description", ""),