fix: allow scroll button tap when idle

static/src/composables/useScrollControl.ts

@@ -54,9 +54,16 @@ export function conditionalScrollToBottom(ctx: ScrollContext) {
 }
 
 export function toggleScrollLock(ctx: ScrollContext) {
-  const nextState = ctx.chatToggleScrollLockState?.() ?? false;
   const active = typeof ctx.isOutputActive === 'function' ? ctx.isOutputActive() : true;
-  if (nextState && active) {
+
+  // 没有模型输出时：允许点击，但不切换锁定，仅单次滚动到底部
+  if (!active) {
+    scrollToBottom(ctx);
+    return ctx.autoScrollEnabled ?? false;
+  }
+
+  const nextState = ctx.chatToggleScrollLockState?.() ?? false;
+  if (nextState) {
     scrollToBottom(ctx);
   }
   return nextState;