fix(app): copy path button styles

packages/app/src/components/session/session-header.tsx

@@ -343,9 +343,10 @@ export function SessionHeader() {
                   <Show
                     when={canOpen()}
                     fallback={
+                      <div class="flex h-[24px] box-border items-center rounded-md border border-border-base bg-surface-panel overflow-hidden">
                         <Button
                           variant="ghost"
-                        class="rounded-sm h-[24px] py-1.5 pr-3 pl-2 gap-2 border-none shadow-none"
+                          class="rounded-none h-full py-0 pr-3 pl-2 gap-2 border-none shadow-none"
                           onClick={copyPath}
                           aria-label={language.t("session.header.open.copyPath")}
                         >
@@ -354,6 +355,7 @@ export function SessionHeader() {
                             {language.t("session.header.open.copyPath")}
                           </span>
                         </Button>
+                      </div>
                     }
                   >
                     <div class="flex items-center">