docs: remove recommended label from pre-built binaries

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: yamitzky

README.md

@@ -16,7 +16,7 @@ CLI & Agent Skill for managing Slack Enterprise Grid / Business+ workspaces via
 
 ## Installation
 
-### Pre-built Binaries (recommended)
+### Pre-built Binaries
 
 Standalone binaries (no runtime required) are available on the [Releases](https://github.com/yamitzky/slack-admin-cli/releases) page:
 

README_ja.md

@@ -16,7 +16,7 @@ Slack Enterprise Grid / Business+ ワークスペースの `admin.*` API を操
 
 ## Installation
 
-### ビルド済みバイナリ（推奨）
+### ビルド済みバイナリ
 
 ランタイム不要のスタンドアロンバイナリを [Releases](https://github.com/yamitzky/slack-admin-cli/releases) ページからダウンロードできます: