Refactor chat component styles for responsiveness and consistency

- Updated padding and margin properties across various chat components to utilize responsive design tokens, ensuring better adaptability to different screen sizes.
- Replaced fixed sizes with responsive variables for buttons, avatars, and bubbles to enhance UI flexibility.
- Adjusted font sizes to use responsive tokens, improving text readability on various devices.
- Standardized border-radius and other dimensions using CSS variables for a cohesive design language.
- Enhanced dialog and screen components with safe area insets for better compatibility with modern devices.

src/app/chat/components/chat-input-bar.module.css

@@ -2,16 +2,17 @@
 
 /* 键盘适配：
  *   --chat-input-lift 是小米 Android + Facebook IAB 的专用抬升值。
- *   env(safe-area-inset-bottom) 处理小米全面屏手势条 / iPhone home indicator。
+ *   --app-safe-bottom 处理小米全面屏手势条 / iPhone home indicator。
  *   正常浏览器中 --chat-input-lift 为 0，因此无视觉副作用。 */
 .bar {
   flex: 0 0 auto;
   padding: 0
-    var(--spacing-lg, 16px)
+    calc(var(--chat-inline-padding, 16px) + var(--app-safe-right, 0px))
     calc(
       var(--spacing-lg, 16px) + var(--chat-input-lift, 0px) +
-        env(safe-area-inset-bottom, 0px)
-    );
+        var(--app-safe-bottom, 0px)
+    )
+    calc(var(--chat-inline-padding, 16px) + var(--app-safe-left, 0px));
   background: transparent;
   transition: padding-top 0.2s ease, padding-bottom 0.2s ease,
     background-color 0.2s ease, box-shadow 0.2s ease;
@@ -30,7 +31,7 @@
   gap: var(--spacing-sm, 8px);
   padding: var(--spacing-sm, 8px);
   background: #fff;
-  border-radius: 32px;
+  border-radius: var(--radius-full, 999px);
   border: 1px solid transparent;
   transition: border-color 0.2s ease;
 }