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/web/lib/wizard/wizard.test.ts

@@ -1,16 +1,31 @@
 import { describe, expect, it } from "vitest";
 
+import type { ProjectPlanView } from "@/lib/api/types";
+
 import {
+  applyPlanPatch,
   canAdvance,
+  canGeneratePlan,
   canSubmit,
   clampStep,
   emptyWizardForm,
+  mapPlanResultToWizardForm,
   STEP_TITLES,
   toCreateRequest,
+  toPlanSeedRequest,
   WIZARD_STEPS,
   type WizardForm,
 } from "./wizard";
 
+const fullPlan: ProjectPlanView = {
+  title_candidates: ["逐光而行", "剑试九霄"],
+  setting: "上古仙门倾轧的洞天世界",
+  narrative_structure: "黄金三章立钩 → 拜师 → 宗门大比爆发",
+  story_core: "废柴少年觉醒禁忌血脉，逆势封神的代价",
+  ending_design: "登顶后归隐，自我救赎收束",
+  tone: "热血",
+};
+
 describe("wizard step metadata", () => {
   it("provides one title per step", () => {
     expect(STEP_TITLES).toHaveLength(WIZARD_STEPS);
@@ -122,6 +137,123 @@ describe("toCreateRequest", () => {
   });
 });
 
+// ⑤ AI 立项方案 → 向导映射（含 ④ 字段 tone；错配字段折进 premise，不静默丢内容）。
+describe("mapPlanResultToWizardForm", () => {
+  it("maps title candidate, structure and tone to their wizard homes", () => {
+    const patch = mapPlanResultToWizardForm(fullPlan);
+    // 书名候选 → title（取首个）。
+    expect(patch.title).toBe("逐光而行");
+    // 叙事结构 → structure。
+    expect(patch.structure).toBe("黄金三章立钩 → 拜师 → 宗门大比爆发");
+    // ④ 字段：基调 → tone。
+    expect(patch.tone).toBe("热血");
+  });
+
+  it("folds setting and ending design into premise without dropping content", () => {
+    const patch = mapPlanResultToWizardForm(fullPlan);
+    // 故事核心 + 时空背景 + 结局设计 逐段拼进 premise（无独立向导字段，不静默丢）。
+    expect(patch.premise).toContain("废柴少年觉醒禁忌血脉，逆势封神的代价");
+    expect(patch.premise).toContain("时空背景：上古仙门倾轧的洞天世界");
+    expect(patch.premise).toContain("结局设计：登顶后归隐，自我救赎收束");
+  });
+
+  it("does not fabricate endingType or narrativePov (④ presets left for author)", () => {
+    // 结局取向/叙事视角是预设枚举，无法从自由文本可靠反推 → 不进 patch（不臆造）。
+    const patch = mapPlanResultToWizardForm(fullPlan);
+    expect(patch.endingType).toBeUndefined();
+    expect(patch.narrativePov).toBeUndefined();
+  });
+
+  it("omits empty fields from the patch (parse resilience)", () => {
+    const empty: ProjectPlanView = {
+      title_candidates: [],
+      setting: "",
+      narrative_structure: "",
+      story_core: "",
+      ending_design: "",
+      tone: "",
+    };
+    expect(mapPlanResultToWizardForm(empty)).toEqual({});
+  });
+});
+
+// applyPlanPatch：按字段并入、仅填空字段（保护作者已编辑内容，非 bulk 覆盖）。
+describe("applyPlanPatch", () => {
+  it("fills only empty fields, preserving author-edited values", () => {
+    const form: WizardForm = {
+      ...emptyWizardForm,
+      title: "作者已取的书名",
+      genre: "仙侠",
+    };
+    const patch = { title: "AI书名", structure: "三幕", tone: "热血" };
+    const next = applyPlanPatch(form, patch);
+    // 已编辑的 title 受保护、不被覆盖；空的 structure/tone 才回填。
+    expect(next.title).toBe("作者已取的书名");
+    expect(next.structure).toBe("三幕");
+    expect(next.tone).toBe("热血");
+    // 未在 patch 中的字段原样保留。
+    expect(next.genre).toBe("仙侠");
+  });
+
+  it("treats whitespace-only fields as empty (fillable)", () => {
+    const form: WizardForm = { ...emptyWizardForm, premise: "   " };
+    const next = applyPlanPatch(form, { premise: "AI 立意" });
+    expect(next.premise).toBe("AI 立意");
+  });
+
+  it("returns a new object without mutating the input form", () => {
+    const form: WizardForm = { ...emptyWizardForm };
+    const next = applyPlanPatch(form, { tone: "热血" });
+    expect(next).not.toBe(form);
+    expect(form.tone).toBe("");
+  });
+});
+
+// canGeneratePlan：种子门控（题材 + logline 都非空）。
+describe("canGeneratePlan", () => {
+  it("requires both genre and logline", () => {
+    expect(canGeneratePlan(emptyWizardForm)).toBe(false);
+    expect(
+      canGeneratePlan({ ...emptyWizardForm, genre: "仙侠" }),
+    ).toBe(false);
+    expect(
+      canGeneratePlan({ ...emptyWizardForm, logline: "一句话" }),
+    ).toBe(false);
+    expect(
+      canGeneratePlan({ ...emptyWizardForm, genre: "仙侠", logline: "一句话" }),
+    ).toBe(true);
+  });
+
+  it("rejects whitespace-only seeds", () => {
+    expect(
+      canGeneratePlan({ ...emptyWizardForm, genre: "  ", logline: "  " }),
+    ).toBe(false);
+  });
+});
+
+// toPlanSeedRequest：向导草稿 → 生成请求（snake_case，空值省略）。
+describe("toPlanSeedRequest", () => {
+  it("serializes seed and filled fields, omitting empties", () => {
+    const form: WizardForm = {
+      ...emptyWizardForm,
+      genre: "都市",
+      logline: "外卖骑手觉醒读心术。",
+      title: "听风者",
+      sellingPoints: ["逆袭"],
+      endingType: "HE",
+    };
+    const req = toPlanSeedRequest(form);
+    expect(req.genre).toBe("都市");
+    expect(req.logline).toBe("外卖骑手觉醒读心术。");
+    expect(req.title).toBe("听风者");
+    expect(req.ending_type).toBe("HE");
+    expect(req.selling_points).toEqual(["逆袭"]);
+    // 空字段省略（undefined），不发空串。
+    expect(req.premise).toBeUndefined();
+    expect(req.tone).toBeUndefined();
+  });
+});
+
 // wizard→create 流程：归一后的请求体经 mock 客户端提交，返回新建项目 id。
 describe("wizard create flow (mocked client)", () => {
   it("submits the normalized body and resolves a project id", async () => {