feat/调整tts音色，调整封面图prompt，修复对话页输入框显示逻辑，待验证封面图生成功能

api/app/features/memoir/service.py

@@ -1,8 +1,10 @@
 """Memoir service — 回忆录编排（章节生成、状态流转）；通过 MemoryService 获取 evidence。"""
 
-from app.core.logging import get_logger
+import uuid
+from datetime import datetime, timezone
 from typing import List, Optional
 
+from app.core.logging import get_logger
 from fastapi import HTTPException
 from sqlalchemy import select
 from sqlalchemy.ext.asyncio import AsyncSession
@@ -18,7 +20,11 @@ from app.features.memoir.helpers import (
     chapter_to_dict,
     is_image_permanently_unavailable,
 )
-from app.features.memoir.models import Book, Chapter, ChapterSection
+from app.features.memoir.models import Book, Chapter, ChapterSection, MemoirImage
+from app.features.memoir.memoir_images.parser import build_initial_image_assets
+from app.features.memoir.memoir_images.serializers import image_dict_to_row_kwargs
+from app.features.memoir.memoir_images.prompting import MemoirImagePromptService
+from app.features.memoir.memoir_images.settings import MemoirImageSettings
 from app.features.memory.service import MemoryService
 
 logger = get_logger(__name__)
@@ -210,6 +216,70 @@ class MemoirService:
             "covered_stages": state.covered_stages,
         }
 
+    async def check_and_trigger_cover_generation(self, user_id: str) -> dict:
+        """
+        检查可生成封面的章节（section 配图 > 3 且无已完成封面），
+        若有则触发生成任务。已有封面的章节不再检查。
+        """
+        from app.tasks.memoir_tasks import generate_chapter_images
+
+        chapters = await repo.get_chapters_with_sections(
+            user_id, self._db, active_only=True, is_new_only=None
+        )
+        triggered: List[str] = []
+        for ch in chapters:
+            if not ch.category or ch.status == "empty":
+                continue
+            sections = getattr(ch, "sections", None) or []
+            section_image_count = sum(1 for s in sections if getattr(s, "image_id", None))
+            images = getattr(ch, "images", None) or []
+            cover_rec = next(
+                (m for m in images if getattr(m, "section_id", None) is None),
+                None,
+            )
+            if section_image_count <= 3:
+                continue
+            if cover_rec and (getattr(cover_rec, "status") or "").strip() == "completed":
+                continue
+            if cover_rec is None:
+                img_settings = MemoirImageSettings.from_env()
+                if img_settings.enabled:
+                    now_iso = datetime.now(timezone.utc).isoformat()
+                    cover_ph = {
+                        "placeholder": "{{{{{{{{IMAGE:章节封面}}}}}}}}",
+                        "description": "章节封面",
+                        "index": 0,
+                    }
+                    style = MemoirImagePromptService.CATEGORY_STYLE_MAP.get(
+                        ch.category or "", img_settings.default_style
+                    )
+                    cover_asset = build_initial_image_assets(
+                        [cover_ph],
+                        img_settings.provider,
+                        style,
+                        img_settings.default_size,
+                        now_iso,
+                    )[0]
+                    kwargs = image_dict_to_row_kwargs(cover_asset)
+                    cover_mi = MemoirImage(
+                        id=str(uuid.uuid4()).replace("-", "")[:32],
+                        chapter_id=ch.id,
+                        section_id=None,
+                        order_index=0,
+                        **kwargs,
+                    )
+                    self._db.add(cover_mi)
+                    await self._db.commit()
+                    await self._db.refresh(ch)
+                    logger.info("创建封面占位: chapter=%s", ch.id)
+            try:
+                generate_chapter_images.delay(ch.id)
+                triggered.append(ch.id)
+                logger.info("触发生成封面: chapter=%s", ch.id)
+            except Exception as exc:
+                logger.warning("封面生成任务派发失败: chapter=%s, error=%s", ch.id, exc)
+        return {"triggered": triggered}
+
     async def mark_memoir_read(self, user_id: str) -> dict:
         stmt = select(Chapter).where(
             Chapter.user_id == user_id, Chapter.is_new == True