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。

1 files changed, 29 insertions, 0 deletions

diff --git a/frontend/src/lib/components/ui/select/select-trigger.svelte b/frontend/src/lib/components/ui/select/select-trigger.svelte
new file mode 100644
index 0000000..3acff3b
--- /dev/null
+++ b/frontend/src/lib/components/ui/select/select-trigger.svelte
@@ -0,0 +1,29 @@
+<script lang="ts">
+	import { Select as SelectPrimitive } from "bits-ui";
+	import ChevronDownIcon from '@lucide/svelte/icons/chevron-down';
+	import { cn, type WithoutChild } from "$lib/utils.js";
+
+	let {
+		ref = $bindable(null),
+		class: className,
+		children,
+		size = "default",
+		...restProps
+	}: WithoutChild<SelectPrimitive.TriggerProps> & {
+		size?: "sm" | "default";
+	} = $props();
+</script>
+
+<SelectPrimitive.Trigger
+	bind:ref
+	data-slot="select-trigger"
+	data-size={size}
+	class={cn(
+		"border-input data-placeholder:text-muted-foreground bg-input/20 dark:bg-input/30 dark:hover:bg-input/50 focus-visible:border-ring focus-visible:ring-ring/30 aria-invalid:ring-destructive/20 dark:aria-invalid:ring-destructive/40 aria-invalid:border-destructive dark:aria-invalid:border-destructive/50 gap-1.5 rounded-md border px-2 py-1.5 text-xs/relaxed transition-colors focus-visible:ring-2 aria-invalid:ring-2 data-[size=default]:h-7 data-[size=sm]:h-6 *:data-[slot=select-value]:flex *:data-[slot=select-value]:gap-1.5 [&_svg:not([class*='size-'])]:size-3.5 flex w-fit items-center justify-between whitespace-nowrap outline-none disabled:cursor-not-allowed disabled:opacity-50 *:data-[slot=select-value]:line-clamp-1 *:data-[slot=select-value]:flex *:data-[slot=select-value]:items-center [&_svg]:pointer-events-none [&_svg]:shrink-0",
+		className
+	)}
+	{...restProps}
+>
+	{@render children?.()}
+	<ChevronDownIcon class="text-muted-foreground size-3.5 pointer-events-none" />
+</SelectPrimitive.Trigger>