feat: add generation trace and partial-ready workflow status

backend/app/services/story_status.py

@@ -10,6 +10,7 @@ class StoryGenerationStatus(str, Enum):
     """Overall story generation lifecycle."""
 
     NARRATIVE_READY = "narrative_ready"
+    PARTIAL_READY = "partial_ready"
     ASSETS_GENERATING = "assets_generating"
     COMPLETED = "completed"
     DEGRADED_COMPLETED = "degraded_completed"
@@ -30,7 +31,10 @@ class StoryLike(Protocol):
 
     story_text: str | None
     pages: list[dict] | None
+    cover_prompt: str | None
+    image_url: str | None
     generation_status: str
+    text_status: str
     image_status: str
     audio_status: str
     last_error: str | None
@@ -55,6 +59,37 @@ def has_narrative_content(story: StoryLike) -> bool:
     return bool(story.story_text) or bool(story.pages)
 
 
+def _has_retryable_image(story: StoryLike, image_status: StoryAssetStatus) -> bool:
+    if image_status in {StoryAssetStatus.READY, StoryAssetStatus.GENERATING}:
+        return False
+
+    pages = story.pages or []
+    has_missing_page_image = any(
+        isinstance(page, dict)
+        and page.get("image_prompt")
+        and not page.get("image_url")
+        for page in pages
+    )
+    return bool(story.cover_prompt and not story.image_url) or has_missing_page_image
+
+
+def _has_pending_assets(
+    story: StoryLike,
+    *,
+    image_status: StoryAssetStatus,
+    audio_status: StoryAssetStatus,
+) -> bool:
+    """Whether readable content still has optional assets to complete."""
+
+    if _has_retryable_image(story, image_status):
+        return True
+
+    return bool(story.story_text) and audio_status not in {
+        StoryAssetStatus.READY,
+        StoryAssetStatus.GENERATING,
+    }
+
+
 def resolve_story_generation_status(story: StoryLike) -> StoryGenerationStatus:
     """Derive the overall status from narrative and asset states."""
 
@@ -70,6 +105,9 @@ def resolve_story_generation_status(story: StoryLike) -> StoryGenerationStatus:
     if StoryAssetStatus.FAILED in (image_status, audio_status):
         return StoryGenerationStatus.DEGRADED_COMPLETED
 
+    if _has_pending_assets(story, image_status=image_status, audio_status=audio_status):
+        return StoryGenerationStatus.PARTIAL_READY
+
     if (
         image_status == StoryAssetStatus.NOT_REQUESTED
         and audio_status == StoryAssetStatus.NOT_REQUESTED
@@ -105,6 +143,12 @@ def sync_story_status(
     if last_error is not _ERROR_UNSET:
         story.last_error = last_error
 
+    story.text_status = (
+        StoryAssetStatus.READY.value
+        if has_narrative_content(story)
+        else StoryAssetStatus.FAILED.value
+    )
+
     generation_status = resolve_story_generation_status(story)
     story.generation_status = generation_status.value