docs: fix markdown syntax and add DeepWiki badge to Korean README

Author: wo-o29

README-ko_kr.md

@@ -1,6 +1,6 @@
 ![](./docs/public/og.png)
 
-# overlay-kit · [![MIT License](https://img.shields.io/badge/license-MIT-blue.svg)](https://github.com/toss/overlay-kit/blob/main/LICENSE) [![codecov](https://codecov.io/gh/toss/overlay-kit/graph/badge.svg?token=JBEAQTL7XK)](https://codecov.io/gh/toss/overlay-kit)
+# overlay-kit · [![MIT License](https://img.shields.io/badge/license-MIT-blue.svg)](https://github.com/toss/overlay-kit/blob/main/LICENSE) [![codecov](https://codecov.io/gh/toss/overlay-kit/graph/badge.svg?token=JBEAQTL7XK)](https://codecov.io/gh/toss/overlay-kit) [![Ask DeepWiki](https://deepwiki.com/badge.svg)](https://deepwiki.com/toss/overlay-kit)
 
 [English](https://github.com/toss/overlay-kit/blob/main/README.md) | 한국어
 

README.md

@@ -70,7 +70,7 @@ import { overlay } from 'overlay-kit';
 
 ## Why use overlay-kit?
 
-### Problems with Traditional Overlay Management**
+### Problems with Traditional Overlay Management
 
 1. Complexity of State Management
  - Had to manage overlay state directly using useState or global state.