docs: bump opencode-openai-codex-auth to v4.2.0 and remove hotfix workaround

- Update all README files (EN, KO, JA, ZH-CN)
- Bump opencode-openai-codex-auth version from 4.1.1 to 4.2.0
- Remove temporary hotfix branch workaround (bug fixed in v4.1.1)
- Simplify OpenAI ChatGPT Plus/Pro setup instructions

🤖 GENERATED WITH ASSISTANCE OF [OhMyOpenCode](https://github.com/code-yeongyu/oh-my-opencode)

Author: code-yeongyu

README.ja.md

@@ -342,24 +342,12 @@ opencode auth login
 {
   "plugin": [
     "oh-my-opencode",
-    "opencode-openai-codex-auth@4.1.1"
+    "opencode-openai-codex-auth@4.2.0"
   ]
 }
 ```
 
-**重要**: 現在、公式 npm パッケージに 400 エラー (`"No tool call found for function call output with call_id"`) を引き起こすバグがあります。修正版がリリースされるまでは、**ホットフィックスブランチの使用を推奨します**。`~/.config/opencode/package.json` を修正してください：
-
-```json
-{
-  "dependencies": {
-    "opencode-openai-codex-auth": "code-yeongyu/opencode-openai-codex-auth#fix/orphaned-function-call-output-with-tools"
-  }
-}
-```
-
-その後、`cd ~/.config/opencode && bun i` を実行してください。`opencode.json` ではバージョン指定なしで `"opencode-openai-codex-auth"` として使用します（`@4.1.0` は除外）。
-
-#### 4.3.1 モデル設定
+##### モデル設定
 `opencode.json` に完全なモデル設定も構成する必要があります。
 [opencode-openai-codex-auth ドキュメント](https://github.com/numman-ali/opencode-openai-codex-auth)を読み、[`config/full-opencode.json`](https://github.com/numman-ali/opencode-openai-codex-auth/blob/main/config/full-opencode.json) から provider/models 設定をコピーして、ユーザーの既存のセットアップを壊さないよう慎重にマージしてください。
 

README.ko.md

@@ -339,24 +339,12 @@ opencode auth login
 {
   "plugin": [
     "oh-my-opencode",
-    "opencode-openai-codex-auth@4.1.1"
+    "opencode-openai-codex-auth@4.2.0"
   ]
 }
 ```
 
-**중요**: 현재 공식 npm 패키지에 400 에러(`"No tool call found for function call output with call_id"`)를 유발하는 버그가 있습니다. 수정 버전이 배포될 때까지 **핫픽스 브랜치 사용을 권장합니다**. `~/.config/opencode/package.json`을 수정하세요:
-
-```json
-{
-  "dependencies": {
-    "opencode-openai-codex-auth": "code-yeongyu/opencode-openai-codex-auth#fix/orphaned-function-call-output-with-tools"
-  }
-}
-```
-
-그 후 `cd ~/.config/opencode && bun i`를 실행하세요. `opencode.json`에서는 버전 없이 `"opencode-openai-codex-auth"`로 사용합니다 (`@4.1.0` 제외).
-
-#### 4.3.1 모델 설정
+##### 모델 설정
 `opencode.json`에 전체 모델 설정도 구성해야 합니다.
 [opencode-openai-codex-auth 문서](https://github.com/numman-ali/opencode-openai-codex-auth)를 읽고, [`config/full-opencode.json`](https://github.com/numman-ali/opencode-openai-codex-auth/blob/main/config/full-opencode.json)에서 provider/models 설정을 복사하여, 사용자의 기존 셋업에 영향을 주지 않도록 깊게 고민하여 적절히 통합하세요.
 

README.md

@@ -373,23 +373,11 @@ First, add the opencode-openai-codex-auth plugin:
 {
   "plugin": [
     "oh-my-opencode",
-    "opencode-openai-codex-auth@4.1.1"
+    "opencode-openai-codex-auth@4.2.0"
   ]
 }
 ```
 
-**Important**: The official npm package currently has a bug causing 400 errors (`"No tool call found for function call output with call_id"`). **Use the hotfix branch** until fixed. Edit `~/.config/opencode/package.json`:
-
-```json
-{
-  "dependencies": {
-    "opencode-openai-codex-auth": "code-yeongyu/opencode-openai-codex-auth#fix/orphaned-function-call-output-with-tools"
-  }
-}
-```
-
-Then run `cd ~/.config/opencode && bun i`. In `opencode.json`, use `"opencode-openai-codex-auth"` without the version suffix.
-
 ##### Model Configuration
 You'll also need full model settings in `opencode.json`.
 Read the [opencode-openai-codex-auth documentation](https://github.com/numman-ali/opencode-openai-codex-auth), copy provider/models config from [`config/full-opencode.json`](https://github.com/numman-ali/opencode-openai-codex-auth/blob/main/config/full-opencode.json), and merge carefully to avoid breaking the user's existing setup.

README.zh-cn.md

@@ -350,23 +350,11 @@ opencode auth login
 {
   "plugin": [
     "oh-my-opencode",
-    "opencode-openai-codex-auth@4.1.1"
+    "opencode-openai-codex-auth@4.2.0"
   ]
 }
 ```
 
-**重要**：现在官方 npm 包有个 bug 会报 400 错（`"No tool call found for function call output with call_id"`）。修复版出来前，**一定要用 hotfix 分支**。改一下 `~/.config/opencode/package.json`：
-
-```json
-{
-  "dependencies": {
-    "opencode-openai-codex-auth": "code-yeongyu/opencode-openai-codex-auth#fix/orphaned-function-call-output-with-tools"
-  }
-}
-```
-
-然后跑 `cd ~/.config/opencode && bun i`。在 `opencode.json` 里用 `"opencode-openai-codex-auth"`（别带版本号）。
-
 ##### 模型配置
 要在 `opencode.json` 里配完整的模型设置。
 去读 [opencode-openai-codex-auth 文档](https://github.com/numman-ali/opencode-openai-codex-auth)，从 [`config/full-opencode.json`](https://github.com/numman-ali/opencode-openai-codex-auth/blob/main/config/full-opencode.json) 抄 provider/models 配置，动脑子合并，别搞炸了。