chore(frontend): shadcn-svelte / Tailwind / layerchart 工具链初始化

[变更性质]
本轮为维护性依赖与配置初始化，不改变业务页面（页面迁移见后续提交）。

[维护内容]
按 Leader 返工指令，前端 UI 组件库全量迁移 shadcn-svelte，图表渲染
从 echarts 换为 layerchart，需要一次性引入配套依赖与构建配置。

[实现方案]
package.json/pnpm-lock.yaml：tailwindcss@4、@tailwindcss/vite、
tw-animate-css、shadcn-svelte、bits-ui、tailwind-variants、clsx、
tailwind-merge、@lucide/svelte、layerchart、@fontsource-variable/inter
与 @types/node；echarts 保留至页面迁移完成后移除。pnpm-workspace.yaml
声明 allowBuilds（esbuild、@tailwindcss/oxide）。components.json 采用
mira preset，别名 $lib。tsconfig 新增 $lib paths；vite.config.ts 加入
tailwindcss 插件、$lib alias（vitest 需要）与 test 环境配置。
src/lib/components/ 为 shadcn 生成的 UI 组件源码（button/input/label/
card/badge/alert/select/table/tabs/separator/chart），src/lib/utils.ts
为 cn 工具。app.css 引入 tailwind 与 shadcn CSS 变量并调整为 teal
主题（primary #0f766e、radius 0.375rem、双主题 chart-1..5），保留
legacy 选择器（banner/beat/table.data/metric 等），mobileCss.test.ts
依赖其语义断言。

[影响范围]
构建链与主题变量；后续页面提交逐步消费这些组件，npm run check/test/
build 已全绿验证。

2 files changed, 51 insertions, 0 deletions

diff --git a/frontend/src/lib/components/ui/badge/badge.svelte b/frontend/src/lib/components/ui/badge/badge.svelte
new file mode 100644
index 0000000..0b34af3
--- /dev/null
+++ b/frontend/src/lib/components/ui/badge/badge.svelte
@@ -0,0 +1,49 @@
+<script lang="ts" module>
+	import { type VariantProps, tv } from "tailwind-variants";
+
+	export const badgeVariants = tv({
+		base: "h-5 gap-1 rounded-full border border-transparent px-2 py-0.5 text-[0.625rem] font-medium transition-all has-data-[icon=inline-end]:pr-1.5 has-data-[icon=inline-start]:pl-1.5 [&>svg]:size-2.5! group/badge inline-flex w-fit shrink-0 items-center justify-center overflow-hidden whitespace-nowrap focus-visible:border-ring focus-visible:ring-[3px] focus-visible:ring-ring/50 aria-invalid:border-destructive aria-invalid:ring-destructive/20 dark:aria-invalid:ring-destructive/40 [&>svg]:pointer-events-none",
+		variants: {
+			variant: {
+				default: "bg-primary text-primary-foreground [a]:hover:bg-primary/80",
+				secondary: "bg-secondary text-secondary-foreground [a]:hover:bg-secondary/80",
+				destructive: "bg-destructive/10 [a]:hover:bg-destructive/20 focus-visible:ring-destructive/20 dark:focus-visible:ring-destructive/40 text-destructive dark:bg-destructive/20",
+				outline: "border-border text-foreground [a]:hover:bg-muted [a]:hover:text-muted-foreground bg-input/20 dark:bg-input/30",
+				ghost: "hover:bg-muted hover:text-muted-foreground dark:hover:bg-muted/50",
+				link: "text-primary underline-offset-4 hover:underline",
+			},
+		},
+		defaultVariants: {
+			variant: "default",
+		},
+	});
+
+	export type BadgeVariant = VariantProps<typeof badgeVariants>["variant"];
+</script>
+
+<script lang="ts">
+	import { cn, type WithElementRef } from "$lib/utils.js";
+	import type { HTMLAnchorAttributes } from "svelte/elements";
+
+	let {
+		ref = $bindable(null),
+		href,
+		class: className,
+		variant = "default",
+		children,
+		...restProps
+	}: WithElementRef<HTMLAnchorAttributes> & {
+		variant?: BadgeVariant;
+	} = $props();
+</script>
+
+<svelte:element
+	this={href ? "a" : "span"}
+	bind:this={ref}
+	data-slot="badge"
+	{href}
+	class={cn(badgeVariants({ variant }), className)}
+	{...restProps}
+>
+	{@render children?.()}
+</svelte:element>
diff --git a/frontend/src/lib/components/ui/badge/index.ts b/frontend/src/lib/components/ui/badge/index.ts
new file mode 100644
index 0000000..64e0aa9
--- /dev/null
+++ b/frontend/src/lib/components/ui/badge/index.ts
@@ -0,0 +1,2 @@
+export { default as Badge } from "./badge.svelte";
+export { badgeVariants, type BadgeVariant } from "./badge.svelte";