fix: 修复历史图标不变色的问题

frontend/src/components/workspace/input-box.tsx

@@ -668,9 +668,26 @@ function HistoryButton({
           router.replace(`/workspace/chats/${threadId}?is_chatting=true`)
         }
       >
-        <svg width="18" height="18" viewBox="0 0 18 18" fill="none" xmlns="http://www.w3.org/2000/svg">
-          <circle cx="9" cy="9" r="8.5" stroke="#150033" />
-          <path d="M9 6V10H12" stroke="#150033" strokeLinecap="round" strokeLinejoin="round" />
+        <svg
+          className="transition-[stroke] duration-200"
+          width="18"
+          height="18"
+          viewBox="0 0 18 18"
+          fill="none"
+          xmlns="http://www.w3.org/2000/svg"
+        >
+          <circle
+            className="stroke-[#150033] transition-[stroke] duration-200 group-hover:stroke-[#8E47F0]"
+            cx="9"
+            cy="9"
+            r="8.5"
+          />
+          <path
+            className="stroke-[#150033] transition-[stroke] duration-200 group-hover:stroke-[#8E47F0]"
+            d="M9 6V10H12"
+            strokeLinecap="round"
+            strokeLinejoin="round"
+          />
         </svg>
 
       </PromptInputButton>