Please address the comments from this code review:

## Overall Comments
- Using a single `saved_cursor_pos_` for all `touch_down` calls may misbehave with multi-touch or overlapping gestures; consider tracking cursor position per contact or only restoring when the corresponding `touch_down`/`touch_up` pair completes.
- Before calling `CGDisplayMoveCursorToPoint` in `touch_up`, it may be safer to track whether a valid cursor position was actually saved (e.g., with a boolean flag) to avoid restoring to an uninitialized or stale position if `touch_down` was skipped or failed.

## Individual Comments

### Comment 1
<location path="source/MaaMacOSControlUnit/Input/GlobalEventInput.mm" line_range="104-105" />
<code_context>
         return false;
     }

+    // 恢复鼠标到 touch_down 之前的位置
+    CGDisplayMoveCursorToPoint(CGMainDisplayID(), saved_cursor_pos_);
+
     return true;
</code_context>
<issue_to_address>
**issue:** Consider what happens if touch_up is called without a prior touch_down (saved_cursor_pos_ is default-initialized).

Because `saved_cursor_pos_` is default-initialized and always used on `touch_up`, calling `touch_up` without a prior successful `touch_down` will reset the cursor to (0,0). Please gate the restore behind a check that a valid position was actually saved (e.g., a boolean flag or tracking that the corresponding contact started).
</issue_to_address>