feat(ui): P3 页面级应用（作品库卡片/空态/加载/设置/次级页）

- 作品库卡片重设计：书脊封面字块 + 衬线书名 + 一句话故事(缺失给占位) +
  元信息行(题材徽章/StatusDot 待审/mono 时间)，Card tone=card 浮起消塌陷
- EmptyState 中性化 + inline/card/bare 变体 + eyebrow（向后兼容）
- loading 骨架化（Skeleton 拼作品库结构，motion-safe）
- 设置页拆分 ProvidersSettings 489→198 + 5 个子组件，凭据点用 StatusDot
- 次级页(向导/模板/codex/大纲)排版字阶与圆角 token 收敛

apps/web/components/projects/ProjectLibrary.tsx

@@ -4,7 +4,7 @@ import Link from "next/link";
 import { Clock3, LayoutGrid, List, Plus, Search } from "lucide-react";
 import { useEffect, useMemo, useState } from "react";
 
-import { ProjectCard } from "@/components/ProjectCard";
+import { ProjectCard } from "@/components/projects/ProjectCard";
 import { Button } from "@/components/ui/Button";
 import { EmptyState } from "@/components/ui/EmptyState";
 import { SegmentedControl } from "@/components/ui/SegmentedControl";
@@ -17,7 +17,7 @@ import {
   type ProjectSort,
   type ProjectViewMode,
 } from "@/lib/projects/projects";
-import { buttonClass, cardClass } from "@/lib/ui/variants";
+import { buttonClass, cardClass, cn, focusRing } from "@/lib/ui/variants";
 
 interface ProjectLibraryProps {
   projects: ProjectResponse[];
@@ -189,16 +189,21 @@ function NewProjectCard() {
   return (
     <Link
       href="/projects/new"
-      className={buttonClass({
-        variant: "outline",
-        className: "group h-full min-h-[176px] flex-col border-dashed text-center",
+      className={cardClass({
+        tone: "soft",
+        flat: true,
+        interactive: true,
+        className: cn(
+          "group flex h-full min-h-[184px] flex-col items-center justify-center gap-3 border-dashed p-5 text-center",
+          focusRing,
+        ),
       })}
     >
-      <span className="mb-3 flex h-10 w-10 items-center justify-center rounded bg-[var(--color-cinnabar-wash)] text-cinnabar transition-colors group-hover:bg-cinnabar group-hover:text-panel">
+      <span className="flex h-12 w-12 items-center justify-center rounded-md bg-[var(--color-cinnabar-wash)] text-cinnabar transition-colors duration-fast ease-standard group-hover:bg-cinnabar group-hover:text-panel">
         <Plus className="h-5 w-5" aria-hidden="true" />
       </span>
-      <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>
+      <span className="font-serif text-title-md text-cinnabar">新建作品</span>
+      <span className="text-caption text-muted-soft">从一句灵感开始一本书</span>
     </Link>
   );
 }