feat(web): Scope B B1 — 多章工作流链前端 UI（发起/轮询/裁决续跑）

链页 app/projects/[id]/chains（RSC fetchProject）+ ChainPage/ChainStarter/
ChainProgress/ChainAdjudication；lib/chain 纯函数（result 收窄/相位映射/resume 组装）。
复用 useJobPoll 轮询、ConflictCard + decisions.ts 裁决、normalizeConflicts/latestReview、
friendlyError；nav 加 chains 入口。awaiting（interrupt）→ 读该章冲突渲 ConflictCard →
POST .../chains/runs/{job_id}/resume 续跑。gen:api 纳入 chains run/resume。
守 #5（链暂停=等裁决，token/正文不入 job result）。

apps/web/lib/nav/items.test.ts

@@ -10,15 +10,16 @@ import {
 const PID = "p1";
 
 describe("projectNavItems", () => {
-  it("builds the nine project entries scoped to the project id", () => {
+  it("builds the ten project entries scoped to the project id", () => {
     const items = projectNavItems(PID);
 
-    expect(items).toHaveLength(9);
+    expect(items).toHaveLength(10);
     expect(items.map((i) => i.key)).toEqual([
       "write",
       "outline",
       "foreshadow",
       "review",
+      "chains",
       "style",
       "codex",
       "toolbox",