chore: remove .pi config from git tracking

.pi 是本地持久化配置目录，不应上传到仓库。
从追踪中移除所有 .pi 文件，并在 .gitignore 顶部添加整体排除规则。
同时修复 pre-commit hook 在 gitignore 文件重 add 时不报错。

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.husky/pre-commit

@@ -38,7 +38,7 @@ fi
 # Restage files that were previously staged and may have been modified by formatting
 for file in $STAGED_FILES; do
   if [ -f "$file" ]; then
-    git add "$file"
+    git add "$file" 2>/dev/null || true
   fi
 done