修复环境变量，UI问题

api/app/features/memoir/memoir_images/settings.py

@@ -21,6 +21,7 @@ class MemoirImageSettings:
     poll_interval_seconds: int = DEFAULT_POLL_INTERVAL_SECONDS
     max_attempts: int = DEFAULT_MAX_ATTEMPTS
     liblib_template_uuid: str = DEFAULT_LIBLIB_TEMPLATE_UUID
+    story_image_min_body_chars: int = 800
 
     @classmethod
     def from_settings(cls, settings: "Settings") -> "MemoirImageSettings":
@@ -33,6 +34,9 @@ class MemoirImageSettings:
             poll_interval_seconds=s.memoir_image_poll_interval,
             max_attempts=s.memoir_image_max_attempts,
             liblib_template_uuid=s.liblib_template_uuid or DEFAULT_LIBLIB_TEMPLATE_UUID,
+            story_image_min_body_chars=int(
+                getattr(s, "story_image_min_body_chars", 800) or 0
+            ),
         )
 
     @classmethod