feat: M1 — 立项→写章草稿(SSE)→自动保存；连一家 provider

- 薄自建 LLM 网关：OpenAI 兼容适配器(DeepSeek) + instructor 结构化输出 + usage_ledger 记账 + 档位路由
- 记忆服务 assemble：确定性选择(显式+主角+近况) + 渲染卡 + 缓存断点(中性文本)
- LangGraph 写章节点 + Postgres checkpointer + SSE 归一(token/done/error)
- API：立项 + 写章 draft(SSE) + PUT 自动保存 + 提供商凭据(Fernet 加密/测试连接)
- 前端：AppShell + 作品库 + 5 步立项向导 + 写作工作台(流式打字机+自动保存) + 设置页
- M1 E2E：真实 DB + mock 网关零 token 走通闭环

apps/web/app/page.tsx

@@ -0,0 +1,80 @@
+import Link from "next/link";
+
+import { AppShell } from "@/components/AppShell";
+import { ProjectCard } from "@/components/ProjectCard";
+import { fetchProjects } from "@/lib/api/server";
+import type { ProjectResponse } from "@/lib/api/types";
+
+// 作品库（Dashboard 入口，UX §6.1）。Server Component 读取。
+export default async function DashboardPage() {
+  let projects: ProjectResponse[] = [];
+  let loadError = false;
+  try {
+    const data = await fetchProjects();
+    projects = data.projects ?? [];
+  } catch {
+    loadError = true;
+  }
+
+  return (
+    <AppShell>
+      <div className="mx-auto max-w-5xl px-8 py-10">
+        <div className="mb-8 flex items-center justify-between">
+          <h1 className="font-serif text-3xl text-ink">我的作品</h1>
+          <Link
+            href="/projects/new"
+            className="rounded bg-cinnabar px-4 py-2 text-sm text-panel hover:opacity-90"
+          >
+            ＋ 新建作品
+          </Link>
+        </div>
+
+        {loadError ? (
+          <p className="rounded border border-conflict bg-panel p-6 text-conflict">
+            无法连接后端服务，请确认 API 已启动后刷新。
+          </p>
+        ) : projects.length === 0 ? (
+          <EmptyState />
+        ) : (
+          <ul className="grid grid-cols-1 gap-5 sm:grid-cols-2 lg:grid-cols-3">
+            {projects.map((p) => (
+              <li key={p.id}>
+                <ProjectCard project={p} />
+              </li>
+            ))}
+            <li>
+              <NewProjectCard />
+            </li>
+          </ul>
+        )}
+      </div>
+    </AppShell>
+  );
+}
+
+function EmptyState() {
+  return (
+    <div className="flex flex-col items-center gap-4 rounded border border-line bg-panel py-20 text-center">
+      <p className="font-serif text-2xl text-ink">还没有作品</p>
+      <p className="text-ink-soft">从一句灵感开始你的第一本书。</p>
+      <Link
+        href="/projects/new"
+        className="rounded bg-cinnabar px-5 py-2 text-sm text-panel hover:opacity-90"
+      >
+        ＋ 新建作品
+      </Link>
+    </div>
+  );
+}
+
+function NewProjectCard() {
+  return (
+    <Link
+      href="/projects/new"
+      className="flex h-full min-h-[160px] flex-col items-center justify-center rounded border border-dashed border-line bg-panel text-center hover:border-cinnabar"
+    >
+      <span className="font-serif text-xl text-cinnabar">＋ 新建</span>
+      <span className="mt-2 text-sm text-ink-soft">从一句灵感开始一本书</span>
+    </Link>
+  );
+}

apps/web/app/projects/[id]/write/page.tsx

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+import { notFound } from "next/navigation";
+
+import { Workbench } from "@/components/workbench/Workbench";
+import { fetchProject } from "@/lib/api/server";
+
+interface PageProps {
+  params: Promise<{ id: string }>;
+}
+
+// 写作工作台页（UX §6.3）。Server Component 取项目，Workbench 负责编辑/流式/保存。
+export default async function WritePage({ params }: PageProps) {
+  const { id } = await params;
+  try {
+    const project = await fetchProject(id);
+    return <Workbench project={project} />;
+  } catch {
+    notFound();
+  }
+}

apps/web/app/projects/new/page.tsx

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+import { AppShell } from "@/components/AppShell";
+import { ProjectWizard } from "@/components/ProjectWizard";
+
+export default function NewProjectPage() {
+  return (
+    <AppShell>
+      <div className="px-8 py-10">
+        <ProjectWizard />
+      </div>
+    </AppShell>
+  );
+}

apps/web/app/settings/providers/page.tsx

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+import { AppShell } from "@/components/AppShell";
+import { ProvidersSettings } from "@/components/settings/ProvidersSettings";
+import { fetchProviders } from "@/lib/api/server";
+import type { ProvidersResponse } from "@/lib/api/types";
+
+// 模型与提供商设置（UX §6.10）。Server Component 取初始数据。
+export default async function ProvidersSettingsPage() {
+  let initial: ProvidersResponse = { providers: [], tier_routing: [] };
+  let loadError = false;
+  try {
+    initial = await fetchProviders();
+  } catch {
+    loadError = true;
+  }
+
+  return (
+    <AppShell title="设置 › 模型与提供商">
+      <div className="mx-auto max-w-3xl px-8 py-10">
+        {loadError ? (
+          <p className="rounded border border-conflict bg-panel p-6 text-conflict">
+            无法连接后端服务，请确认 API 已启动后刷新。
+          </p>
+        ) : (
+          <ProvidersSettings initial={initial} />
+        )}
+      </div>
+    </AppShell>
+  );
+}