build: 引入tailwindcss并迁移原有样式到原子类

1. 新增postcss、autoprefixer、tailwindcss依赖并初始化配置
2. 移除全局及页面级CSS文件，将样式替换为tailwind原子类
3. 重构API调用逻辑，拆分接口请求函数
4. 统一项目样式规范，优化布局与组件样式

src/index.css

@@ -1,42 +1,48 @@
-* {
-  box-sizing: border-box;
+@tailwind base;
+@tailwind components;
+@tailwind utilities;
+
+@layer base {
+  * {
+    @apply box-border;
+  }
+
+  html,
+  body,
+  #root {
+    @apply m-0 min-h-full w-full min-w-80;
+  }
+
+  body {
+    @apply bg-canvas font-sans text-ink;
+  }
+
+  button,
+  input,
+  textarea,
+  select {
+    font: inherit;
+  }
 }
 
-html,
-body,
-#root {
-  width: 100%;
-  min-width: 320px;
-  min-height: 100%;
-  margin: 0;
-}
+@layer components {
+  .section-card {
+    @apply rounded-lg;
+  }
 
-body {
-  color: #1d2129;
-  background: #f2f3f5;
-  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
-}
+  .page-stack {
+    @apply flex flex-col gap-4;
+  }
 
-button,
-input,
-textarea,
-select {
-  font: inherit;
-}
+  .modal-actions {
+    @apply mt-6 flex justify-end gap-3;
+  }
 
-.section-card {
-  border-radius: 8px;
-}
+  .form-label {
+    @apply mb-2 text-sm font-medium text-[#4e5969];
+  }
 
-.page-stack {
-  display: flex;
-  flex-direction: column;
-  gap: 16px;
-}
-
-.modal-actions {
-  display: flex;
-  justify-content: flex-end;
-  gap: 12px;
-  margin-top: 24px;
+  .form-help {
+    @apply -mt-3 mb-[18px] text-[13px] leading-[1.6] text-muted;
+  }
 }