fix(icon): auto-apply default color from metadata when color prop is not provided

When ProviderIcon is used without a color prop, it now automatically
fetches the defaultColor from icon metadata. This fixes the issue where
Gemini app icon turns black when selected in AppSwitcher, because the
component was inheriting the parent's text-foreground color.

src/components/ProviderIcon.tsx

@@ -1,5 +1,5 @@
 import React, { useMemo } from "react";
-import { getIcon, hasIcon } from "@/icons/extracted";
+import { getIcon, hasIcon, getIconMetadata } from "@/icons/extracted";
 import { cn } from "@/lib/utils";
 
 interface ProviderIconProps {
@@ -39,6 +39,19 @@ export const ProviderIcon: React.FC<ProviderIconProps> = ({
     };
   }, [size]);
 
+  // 获取有效颜色：优先使用传入的 color，否则从元数据获取 defaultColor
+  const effectiveColor = useMemo(() => {
+    if (color) return color;
+    if (icon) {
+      const metadata = getIconMetadata(icon);
+      // 只有当 defaultColor 不是 currentColor 时才使用
+      if (metadata?.defaultColor && metadata.defaultColor !== "currentColor") {
+        return metadata.defaultColor;
+      }
+    }
+    return undefined;
+  }, [color, icon]);
+
   // 如果有图标，显示图标
   if (iconSvg) {
     return (
@@ -47,7 +60,7 @@ export const ProviderIcon: React.FC<ProviderIconProps> = ({
           "inline-flex items-center justify-center flex-shrink-0",
           className,
         )}
-        style={{ ...sizeStyle, color }}
+        style={{ ...sizeStyle, color: effectiveColor }}
         dangerouslySetInnerHTML={{ __html: iconSvg }}
       />
     );

src/icons/extracted/index.ts

@@ -65,3 +65,5 @@ export function getIcon(name: string): string {
 export function hasIcon(name: string): boolean {
   return name.toLowerCase() in icons;
 }
+
+export { getIconMetadata } from "./metadata";