docs: Update current plan directory path in copilot instructions

Signed-off-by: FrozenlemonTee <1115306170@qq.com>

Author: FrozenLemonTee

.github/copilot-instructions.md

@@ -14,7 +14,7 @@
 
 ## 正在进行中的计划
 
-- 当前计划目录：`../.github/prompts/`
+- 当前计划目录：`../.agents/docs/plans/`
 
 ## 说明