feat(M7): 第11环裂变引擎端到端打通

- fission_service: 1源任务扇出N套子任务(回填source_fission_id,复用主管道),MAX_FANOUT=5红线
- fission_prompt: 三档参考度(high/mid/low)占位规则,真实措辞待北哥定义
- tasks.py: worker识别裂变子任务→注入对应档位规则进文案上下文(关键缺口修复)
- api/v1/fission: POST触发 + GET进度聚合, main.py注册路由
- 实测: fission_id=2扇出task70/71,worker注入日志level=high,进度端点聚合正确

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

backend/app/api/v1/fission.py

@@ -0,0 +1,78 @@
+"""
+app/api/v1/fission.py — 第11环裂变路由
+
+POST /fission           触发裂变(1源任务→N套子任务)
+GET  /fission/{id}      查裂变进度(聚合N个子任务状态)
+工作台内呈现,子任务走标准 SSE 流回进度。
+"""
+import logging
+from typing import Annotated
+
+from fastapi import APIRouter, Depends
+from pydantic import BaseModel, Field
+from sqlalchemy.orm import Session
+
+from app.core.database import get_db
+from app.core.response import ok, raise_not_found
+from app.middleware.workspace_guard import CurrentUser, require_write_permission
+from app.models.fission import FissionTask
+from app.models.task import GenerationTask
+
+logger = logging.getLogger(__name__)
+router = APIRouter(tags=["fission"])
+
+
+class FissionCreate(BaseModel):
+    source_task_id: int
+    reference_level: str = Field(default="mid")   # low/mid/high
+    fanout_count: int = Field(default=3, ge=1, le=5)
+
+
+@router.post("/fission")
+def create_fission_endpoint(
+    body: FissionCreate,
+    current_user: Annotated[CurrentUser, Depends(require_write_permission)] = None,
+    db: Session = Depends(get_db),
+):
+    """触发裂变：从源任务扇出 N 套完整笔记包。返回 fission_id + 子 task_ids。"""
+    from app.services.fission_service import create_fission
+    fission_id, task_ids = create_fission(
+        db, current_user, body.source_task_id, body.reference_level, body.fanout_count,
+    )
+    return ok({"fission_id": fission_id, "task_ids": task_ids,
+               "reference_level": body.reference_level, "fanout_count": len(task_ids)})
+
+
+@router.get("/fission/{fission_id}")
+def get_fission_progress(
+    fission_id: int,
+    current_user: Annotated[CurrentUser, Depends(require_write_permission)] = None,
+    db: Session = Depends(get_db),
+):
+    """查裂变进度：聚合 N 个子任务状态（x/N 完成）。"""
+    ft = db.query(FissionTask).filter(
+        FissionTask.id == fission_id,
+        FissionTask.workspace_id == current_user.workspace_id,
+    ).first()
+    if not ft:
+        raise_not_found("裂变任务不存在")
+
+    subs = db.query(GenerationTask).filter(
+        GenerationTask.source_fission_id == fission_id,
+        GenerationTask.workspace_id == current_user.workspace_id,
+    ).all()
+    done_states = {"pending_selection", "pending_review", "approved", "archived"}
+    done = sum(1 for s in subs if s.status in done_states)
+    failed = sum(1 for s in subs if s.status == "failed")
+    total = len(subs)
+    # 聚合状态：全失败=failed,全完成=done,否则generating
+    agg = "done" if done == total and total > 0 else ("failed" if failed == total and total > 0 else "generating")
+    if ft.status != agg:
+        ft.status = agg; db.commit()
+
+    return ok({
+        "fission_id": ft.id, "reference_level": ft.reference_level,
+        "fanout_count": ft.fanout_count, "status": agg,
+        "progress": {"done": done, "failed": failed, "total": total},
+        "task_ids": [s.id for s in subs],
+    })

backend/app/services/ai_engine/fission_prompt.py

@@ -0,0 +1,43 @@
+"""
+app/services/ai_engine/fission_prompt.py — 第11环裂变 三档参考度 prompt
+
+裂变=1爆款→N套完整笔记包。参考度档位控制"新套子贴原爆款多紧"：
+  high=贴原爆款结构+卖点(最像) / mid=保卖点换叙事角度 / low=只借选题方向(最自由)
+
+🔴 占位规则(倩倩姐2026-06-16:先移植打通再请北哥定档位)。
+   档位真实措辞待北哥定义后替换 _LEVEL_RULES,引擎链路不动。
+"""
+
+# 三档占位规则：注入文案引擎 flywheel_context，约束"参考原爆款多少"
+_LEVEL_RULES = {
+    "high": (
+        "【裂变参考度=高】请紧贴下面这篇原爆款的正文结构、开头钩子、卖点排布与情绪语气，"
+        "近乎仿写——只替换表达措辞做到不查重，骨架与卖点角度都保留。"
+    ),
+    "mid": (
+        "【裂变参考度=中】请保留下面这篇原爆款的核心卖点，但换一个全新的叙事角度/切入场景重写，"
+        "结构可调整，让读者看不出是同一套路。"
+    ),
+    "low": (
+        "【裂变参考度=低】请只借鉴下面这篇原爆款的选题方向与目标人群，"
+        "文案结构、卖点呈现、叙事全部自由发挥，做出明显差异化的新笔记。"
+    ),
+}
+
+
+def build_fission_context(source_note: dict, reference_level: str) -> str:
+    """
+    返回注入 text_variants(flywheel_context=) 的档位规则字符串。
+    source_note: {title, content, ...} 原爆款笔记内容。
+    reference_level: high/mid/low，非法值回落 mid。
+    """
+    rule = _LEVEL_RULES.get(reference_level, _LEVEL_RULES["mid"])
+    title = (source_note or {}).get("title", "")
+    content = (source_note or {}).get("content", "")
+    src = f"原爆款标题：{title}\n原爆款正文：{content}".strip()
+    return f"{rule}\n\n--- 原爆款参考 ---\n{src}"
+
+
+def valid_level(level: str | None) -> str:
+    """校验档位，非法回落 mid。"""
+    return level if level in _LEVEL_RULES else "mid"

backend/app/services/fission_service.py

@@ -0,0 +1,84 @@
+"""
+app/services/fission_service.py — 第11环裂变 扇出 service
+
+1爆款 → N套完整笔记包。每套=一个独立 GenerationTask(回填 source_fission_id),
+复用主管道 run_generation_pipeline 生成文案+配图。
+🔴 占位档位规则见 fission_prompt.py,真实措辞待北哥定义(倩倩姐2026-06-16先打通)。
+"""
+import json
+import logging
+
+from sqlalchemy.orm import Session
+
+from app.core.response import raise_business
+from app.middleware.workspace_guard import CurrentUser
+from app.models.fission import FissionTask
+from app.models.task import GenerationTask
+from app.services.ai_engine.fission_prompt import valid_level
+from app.services.task_service import _check_user_has_key, enqueue_generation
+
+logger = logging.getLogger(__name__)
+
+MAX_FANOUT = 5  # 每用户并发上限5(红线),裂变扇出数受同等约束
+
+
+def create_fission(
+    db: Session, current_user: CurrentUser,
+    source_task_id: int, reference_level: str, fanout_count: int,
+) -> tuple[int, list[int]]:
+    """
+    从一个源任务裂变出 N 套子任务。
+    返回 (fission_id, [子task_id,...])。
+    """
+    _check_user_has_key(db, current_user.user_id, current_user.workspace_id)
+
+    level = valid_level(reference_level)
+    n = max(1, min(fanout_count or 3, MAX_FANOUT))
+
+    # 读源任务(取产品+主题+已选文案作为爆款源)
+    src = db.query(GenerationTask).filter(
+        GenerationTask.id == source_task_id,
+        GenerationTask.workspace_id == current_user.workspace_id,
+    ).first()
+    if not src:
+        raise_business("裂变源任务不存在")
+
+    source_note = {"title": src.theme or "", "content": _extract_source_copy(db, src)}
+
+    # 建 fission_task 记录
+    ft = FissionTask(
+        workspace_id=current_user.workspace_id,
+        source_note=json.dumps(source_note, ensure_ascii=False),
+        reference_level=level, fanout_count=n, status="generating",
+    )
+    db.add(ft); db.commit(); db.refresh(ft)
+
+    # 扇出 N 个子任务(回填 source_fission_id),复用主管道
+    task_ids: list[int] = []
+    for _ in range(n):
+        sub = GenerationTask(
+            workspace_id=current_user.workspace_id,
+            product_id=src.product_id, operator_id=current_user.user_id,
+            theme=src.theme, text_count=src.text_count, image_count=src.image_count,
+            track="ai", need_product_image=src.need_product_image,
+            status="pending", source_fission_id=ft.id,
+        )
+        db.add(sub); db.commit(); db.refresh(sub)
+        enqueue_generation(sub.id)
+        task_ids.append(sub.id)
+
+    logger.info("fission created id=%s level=%s fanout=%s tasks=%s",
+                ft.id, level, n, task_ids)
+    return ft.id, task_ids
+
+
+def _extract_source_copy(db: Session, src: GenerationTask) -> str:
+    """取源任务已选/最高分文案当爆款正文;无则用主题兜底。"""
+    from app.models.task import TextCandidate
+    c = (db.query(TextCandidate)
+         .filter(TextCandidate.task_id == src.id)
+         .order_by(TextCandidate.is_selected.desc(), TextCandidate.id.asc())
+         .first())
+    if c and c.content:
+        return c.content
+    return src.theme or ""

backend/app/workers/tasks.py

@@ -92,6 +92,22 @@ def run_generation_pipeline(self, task_id: int) -> dict:
         product_dict = build_product_dict(product)
         flywheel_fragment, flywheel_ctx = load_flywheel_context(db, workspace_id, task.product_id, product_dict)
 
+        # 第11环裂变:子任务(source_fission_id非空)按裂变档位+源爆款生成,拼进文案上下文。
+        if getattr(task, "source_fission_id", None):
+            import json as _json
+            from app.models.fission import FissionTask
+            from app.services.ai_engine.fission_prompt import build_fission_context
+            ft = db.query(FissionTask).filter(FissionTask.id == task.source_fission_id).first()
+            if ft:
+                try:
+                    src_note = _json.loads(ft.source_note) if ft.source_note else {}
+                except Exception:
+                    src_note = {}
+                fission_ctx = build_fission_context(src_note, ft.reference_level)
+                flywheel_fragment = f"{fission_ctx}\n\n{flywheel_fragment}".strip()
+                logger.info("裂变子任务注入档位: task_id=%s fission=%s level=%s",
+                            task_id, ft.id, ft.reference_level)
+
         if flywheel_fragment:
             seq += 1
             _push_event_sync(task_id, workspace_id, "flywheel_injected", {