feat(web): AI 立项方案生成+预填（种子门控 + 按字段接受）

向导阶段（project 未建）一键推演结构化书级蓝图预填立项向导。

- 新 SPEC project_plan_spec（analyst 档，纯预览 reads/writes=()）+ schema
  ProjectPlanResult（书名候选 + 时空背景/叙事结构/故事核心/结局设计/基调，
  全字段默认值守解析韧性）+ 注册 SCHEMA_CATALOG；计数三处 21→22 + regen golden。
- 端点 POST /skills/project-plan/generate（不带 project 前缀，绕开 toolbox 404）：
  请求体序列化向导草稿为 project_context，复用 build_brief_context + run_generator；
  种子门控（缺 genre/logline→422）；请求 schema 加 max_length 上界。
- run_generator/_build_request 的 project_id 放宽 uuid.UUID|None（向导无 project）。
- 前端 wizard.ts 加 mapPlanResultToWizardForm（错配字段折进 premise 不静默丢）+
  applyPlanPatch（仅回填空字段、保护已编辑）+ useProjectPlan hook + PlanAssistant。

apps/api/ww_api/routers/generation.py

@@ -26,8 +26,10 @@ from sqlalchemy.ext.asyncio import AsyncSession
 from ww_agents import (
     CharacterCard,
     CharacterRelation,
+    ProjectPlanResult,
     character_gen_spec,
     continuity_spec,
+    project_plan_spec,
     worldbuilder_spec,
 )
 from ww_core.domain import (
@@ -37,8 +39,10 @@ from ww_core.domain import (
 )
 from ww_core.domain.repositories import MemoryRepos
 from ww_core.orchestrator import (
+    build_brief_context,
     precheck_generated_cards,
     run_character_gen,
+    run_generator,
     run_worldbuilder,
 )
 from ww_db import get_session
@@ -64,6 +68,7 @@ from ww_api.schemas.generation import (
     WorldGenerateRequest,
     WorldGenPreviewResponse,
 )
+from ww_api.schemas.projects import ProjectPlanGenerateRequest, ProjectPlanView
 from ww_api.schemas.rules import RuleView
 from ww_api.services.credentials import STUB_OWNER_ID
 from ww_api.services.project_deps import (
@@ -71,6 +76,7 @@ from ww_api.services.project_deps import (
     get_character_write_repo,
     get_memory_repos,
     get_precheck_gateway,
+    get_project_plan_gateway,
     get_project_repo,
     get_rule_write_repo,
     get_skill_registry,
@@ -90,6 +96,7 @@ SkillRegistryDep = Annotated[SkillRegistry, Depends(get_skill_registry)]
 WorldGatewayDep = Annotated[Gateway, Depends(get_worldbuilder_gateway)]
 CharacterGatewayDep = Annotated[Gateway, Depends(get_character_gen_gateway)]
 PrecheckGatewayDep = Annotated[Gateway, Depends(get_precheck_gateway)]
+ProjectPlanGatewayDep = Annotated[Gateway, Depends(get_project_plan_gateway)]
 SessionDep = Annotated[AsyncSession, Depends(get_session)]
 
 
@@ -105,6 +112,46 @@ def _project_context(title: str, genre: str | None, premise: str | None, theme:
     return "\n".join(lines)
 
 
+def _plan_seed_context(body: ProjectPlanGenerateRequest) -> str:
+    """把立项向导草稿序列化为作品种子（喂 project-plan；仿 `_project_context`）。
+
+    确定性、无时间戳/UUID；只拼非空字段（有则贴合、无则不臆造）。
+    genre + logline 由端点种子门控保证非空。
+    """
+    lines: list[str] = []
+    label_fields: list[tuple[str, str | None]] = [
+        ("暂定书名", body.title),
+        ("题材", body.genre),
+        ("一句话故事", body.logline),
+        ("立意", body.premise),
+        ("主题", body.theme),
+        ("故事结构", body.structure),
+        ("基调", body.tone),
+        ("结局取向", body.ending_type),
+        ("叙事视角", body.narrative_pov),
+    ]
+    for label, value in label_fields:
+        text = (value or "").strip()
+        if text:
+            lines.append(f"{label}：{text}")
+    points = [p.strip() for p in body.selling_points if p.strip()]
+    if points:
+        lines.append(f"核心卖点：{'、'.join(points)}")
+    return "\n".join(lines)
+
+
+def _plan_to_view(plan: ProjectPlanResult) -> ProjectPlanView:
+    """ww_agents.ProjectPlanResult → API ProjectPlanView（字段同名直传）。"""
+    return ProjectPlanView(
+        title_candidates=list(plan.title_candidates),
+        setting=plan.setting,
+        narrative_structure=plan.narrative_structure,
+        story_core=plan.story_core,
+        ending_design=plan.ending_design,
+        tone=plan.tone,
+    )
+
+
 def _render_characters_context(cards: list[CharacterCard]) -> str:
     """已有角色简表（喂 character-gen 防雷同 + precheck 真相源）。确定性、保序。"""
     if not cards:
@@ -430,6 +477,53 @@ async def list_skills(registry: SkillRegistryDep) -> SkillListResponse:
     return SkillListResponse(skills=skills)
 
 
+# ---- AI 立项方案生成（灵感⑤；不带 project 前缀，立项前 project 未建）----
+
+
+@skills_router.post("/project-plan/generate")
+async def generate_project_plan(
+    body: ProjectPlanGenerateRequest,
+    request: Request,
+    gateway: ProjectPlanGatewayDep,
+    session: SessionDep,
+) -> ProjectPlanView:
+    """生成结构化立项方案预览（向导阶段，project 未建，不入库）。
+
+    **不带 project 前缀**——绕开 toolbox 的 `project_repo.get→404`（立项前无 project）。
+    **种子门控**：缺 genre 或 logline → 422（空向导不出方案，防 slop）。无凭据 → 503。
+    """
+    request_id = getattr(request.state, "request_id", None)
+    genre = (body.genre or "").strip()
+    logline = (body.logline or "").strip()
+    if not genre or not logline:
+        raise AppError(
+            ErrorCode.VALIDATION,
+            "生成立项方案至少需要「题材」与「一句话故事（logline）」两个种子",
+            {"has_genre": bool(genre), "has_logline": bool(logline)},
+        )
+
+    project_context = _plan_seed_context(body)
+    context = build_brief_context(brief=body.brief or "", project_context=project_context)
+    parsed = await run_generator(
+        project_plan_spec,
+        context=context,
+        gateway=gateway,
+        user_id=STUB_OWNER_ID,
+        project_id=None,  # 向导阶段 project 未建；usage_ledger.project_id 可空
+    )
+    # 提交边界：预览不写业务表，但网关 ledger 只 flush → 末尾 commit 落 usage（否则丢失）。
+    await session.commit()
+    if not isinstance(parsed, ProjectPlanResult):
+        # run_generator 已按 output_schema 校验；防御性收窄（不应触达）。
+        raise AppError(ErrorCode.INTERNAL, "立项方案生成返回类型异常")
+    log.info(
+        "project_plan_generate_done",
+        request_id=request_id,
+        title_count=len(parsed.title_candidates),
+    )
+    return _plan_to_view(parsed)
+
+
 # ---- schema <-> ww_agents 卡转换 ----