裂变补图：中转站波动导致单张失败时只重生失败分镜

实测发现 codeproxy 偶发不稳，单套中某张图重试3次仍失败会记 error。
本次加按需补图：只重生标 error 的分镜，成功的图与 token 不浪费。

- 019迁移+模型：fission_tasks 加 source_task_id(新架构不扇出GenerationTask,
  补图需复刻首轮上下文:产品/operator key/张数,故落库回查)
- fission_image_retry：只补失败 role(引擎 target_role 单张重生,R2零改动),
  merge 回 images_json,全恢复则 status=image_done
- tasks.py：retry_fission_images Celery task,key归属源任务operator(基石B),
  幂等锁防重复补图
- api：POST /fission/{id}/notes/{seq}/retry-images,无失败分镜守卫 queued=false
- 前端：FissionNoteCard 失败提示改"重试补图"按钮+loading,父页轮询刷新

实测task5 seq1(hook图首轮codeproxy重试3次失败)补图跑通：只补hook(1024×1536
去AI化)、applied_proof原图不动、recovered=1 still_failed=0、status=image_done;
apiports503回落codeproxy gpt-5.5强档兜底;seq0无失败图守卫queued=false

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

backend/app/services/fission_image_retry.py

@@ -0,0 +1,105 @@
+"""
+app/services/fission_image_retry.py — 第11环裂变 失败分镜补图（中转站波动兜底）
+
+实测发现 codeproxy 偶发不稳，单套中某张图重试3次仍失败会记 error 落库。
+本模块对某一套(FissionNote)只补 images_json 里标了 error 的分镜：成功的不动，
+失败的用引擎 target_role 单张重生(R2 零改动)，merge 回 images_json。
+
+🔴 生图引擎零改动；只补失败 role，避免整套重生浪费已成功的图与 token。
+"""
+import logging
+
+from sqlalchemy.orm import Session
+
+logger = logging.getLogger(__name__)
+
+
+def _failed_roles(images: list[dict]) -> list[str]:
+    """从 images_json 解析出标了 error 的分镜 role 列表。"""
+    return [img.get("role", "") for img in images if img.get("error") and img.get("role")]
+
+
+def retry_fission_note_images(
+    db: Session, clients, ft, product: dict, image_count: int, note_id: int,
+) -> dict:
+    """对单套 FissionNote 只补失败分镜。返回 {seq, retried, recovered, still_failed}。"""
+    import asyncio
+    import json as _json
+    import os
+
+    from app.models.fission import FissionNote
+    from app.core.config import get_settings
+    from app.services.ai_engine.image_gen import generate_storyboard_images
+    from app.services.ai_engine.image_postprocessor import process_image
+    from app.workers.pipeline_io import _resolve_image_path
+
+    fn = db.query(FissionNote).filter(FissionNote.id == note_id).first()
+    if not fn:
+        return {"seq": None, "retried": 0, "recovered": 0, "still_failed": 0}
+
+    try:
+        images = _json.loads(fn.images_json) if fn.images_json else []
+    except (ValueError, TypeError):
+        images = []
+    try:
+        note = _json.loads(fn.note_json) if fn.note_json else {}
+    except (ValueError, TypeError):
+        note = {}
+
+    failed = _failed_roles(images)
+    if not failed:
+        return {"seq": fn.seq, "retried": 0, "recovered": 0, "still_failed": 0}
+
+    # 参考图沿用源产品同一张（与首轮生图一致）
+    reference_images = None
+    _img_path = _resolve_image_path(product.get("image_path", ""))
+    if _img_path and os.path.isfile(_img_path):
+        try:
+            with open(_img_path, "rb") as f:
+                reference_images = [f.read()]
+        except Exception as e:  # noqa: BLE001
+            logger.warning("裂变补图参考图读取失败，无参考图模式: %s", e)
+
+    upload_base = get_settings().UPLOAD_ABS_ROOT
+    img_dir = os.path.join(upload_base, str(ft.workspace_id), f"fission_{ft.id}", str(fn.seq))
+    os.makedirs(img_dir, exist_ok=True)
+
+    recovered = 0
+    # role → 在 images 列表里的位置(保持原顺序/seq 不乱)
+    role_idx = {img.get("role"): i for i, img in enumerate(images)}
+    for role in failed:
+        try:
+            results = asyncio.run(generate_storyboard_images(
+                client=clients, note=note, product=product,
+                image_count=image_count, reference_images=reference_images,
+                target_role=role,
+            ))
+        except Exception as exc:  # noqa: BLE001
+            logger.error("裂变补图 seq=%s role=%s 仍失败: %s", fn.seq, role, exc)
+            continue
+        r = next((x for x in results if x.get("role") == role), None)
+        if not r or r.get("error") or not r.get("image_bytes"):
+            logger.warning("裂变补图 seq=%s role=%s 引擎返回空/error", fn.seq, role)
+            continue
+        try:
+            processed = process_image(r["image_bytes"], aspect_ratio="3:4", resample_strength=1)
+        except Exception:  # noqa: BLE001
+            processed = r["image_bytes"]
+        idx = role_idx.get(role, len(images))
+        seq_no = idx + 1
+        fname = f"{seq_no:02d}_{role}.jpg"
+        with open(os.path.join(img_dir, fname), "wb") as f:
+            f.write(processed)
+        entry = {"role": role, "seq": seq_no,
+                 "url": f"/uploads/{ft.workspace_id}/fission_{ft.id}/{fn.seq}/{fname}"}
+        if idx < len(images):
+            images[idx] = entry
+        else:
+            images.append(entry)
+        recovered += 1
+
+    fn.images_json = _json.dumps(images, ensure_ascii=False)
+    still = len(_failed_roles(images))
+    fn.status = "image_done" if still == 0 else fn.status
+    db.commit()
+    return {"seq": fn.seq, "retried": len(failed), "recovered": recovered, "still_failed": still}

backend/app/services/fission_service.py

@@ -51,6 +51,7 @@ def create_fission(
     ft = FissionTask(
         workspace_id=current_user.workspace_id,
         source_note=json.dumps(source_note, ensure_ascii=False),
+        source_task_id=source_task_id,
         reference_level=level, fanout_count=n, status="generating",
     )
     db.add(ft); db.commit(); db.refresh(ft)