fix: externalize @ast-grep/napi for cross-platform support, add installation docs

README.en.md

@@ -3,6 +3,7 @@ English | [한국어](README.ko.md)
 ## Contents
 
 - [Oh My OpenCode](#oh-my-opencode)
+  - [Installation](#installation)
   - [TL;DR](#tldr)
   - [Why OpenCode \& Why Oh My OpenCode](#why-opencode--why-oh-my-opencode)
   - [Features](#features)
@@ -29,6 +30,18 @@ You don't write code just for a paycheck? You write because you genuinely love i
 
 To you, OpenCode will feel like the paradigm shift from Windows to Linux. Not you? It's still worth the investment. Give it 10 minutes. Your work and life will improve. I promise.
 
+## Installation
+
+Add to `~/.config/opencode/opencode.json`:
+
+```json
+{
+  "plugin": [
+    "oh-my-opencode"
+  ]
+}
+```
+
 ## TL;DR
 
 - **Model Setup Required**
@@ -135,6 +148,4 @@ As of now, I have no affiliation with any of the projects or models mentioned he
 
 - I constructed 99% of this project using OpenCode. I focused on functional verification. This documentation has been personally reviewed and comprehensively rewritten, so you can rely on it with confidence.
 
----
 
-I currently don't have access to my NPM account. I'll update this section as soon as I get it back.