docs: update repository references from glittercowboy to gsd-build

The repository was transferred from the glittercowboy org to gsd-build,
but several files still referenced the old org in URLs. This updates all
repository URL references across READMEs (all languages), package.json,
and the update workflow. Also removes a duplicate language selector in
the main README header.

Files intentionally unchanged:
- CHANGELOG.md (historical entries)
- CODEOWNERS, FUNDING.yml, SECURITY.md (reference @glittercowboy as a
  GitHub username/handle, not a repo URL)

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

README.ja-JP.md

@@ -12,11 +12,11 @@
 
 [![npm version](https://img.shields.io/npm/v/get-shit-done-cc?style=for-the-badge&logo=npm&logoColor=white&color=CB3837)](https://www.npmjs.com/package/get-shit-done-cc)
 [![npm downloads](https://img.shields.io/npm/dm/get-shit-done-cc?style=for-the-badge&logo=npm&logoColor=white&color=CB3837)](https://www.npmjs.com/package/get-shit-done-cc)
-[![Tests](https://img.shields.io/github/actions/workflow/status/glittercowboy/get-shit-done/test.yml?branch=main&style=for-the-badge&logo=github&label=Tests)](https://github.com/glittercowboy/get-shit-done/actions/workflows/test.yml)
+[![Tests](https://img.shields.io/github/actions/workflow/status/gsd-build/get-shit-done/test.yml?branch=main&style=for-the-badge&logo=github&label=Tests)](https://github.com/gsd-build/get-shit-done/actions/workflows/test.yml)
 [![Discord](https://img.shields.io/badge/Discord-Join-5865F2?style=for-the-badge&logo=discord&logoColor=white)](https://discord.gg/gsd)
 [![X (Twitter)](https://img.shields.io/badge/X-@gsd__foundation-000000?style=for-the-badge&logo=x&logoColor=white)](https://x.com/gsd_foundation)
 [![$GSD Token](https://img.shields.io/badge/$GSD-Dexscreener-1C1C1C?style=for-the-badge&logo=data:image/svg+xml;base64,PHN2ZyB3aWR0aD0iMjQiIGhlaWdodD0iMjQiIHZpZXdCb3g9IjAgMCAyNCAyNCIgZmlsbD0ibm9uZSIgeG1sbnM9Imh0dHA6Ly93d3cudzMub3JnLzIwMDAvc3ZnIj48Y2lyY2xlIGN4PSIxMiIgY3k9IjEyIiByPSIxMCIgZmlsbD0iIzAwRkYwMCIvPjwvc3ZnPg==&logoColor=00FF00)](https://dexscreener.com/solana/dwudwjvan7bzkw9zwlbyv6kspdlvhwzrqy6ebk8xzxkv)
-[![GitHub stars](https://img.shields.io/github/stars/glittercowboy/get-shit-done?style=for-the-badge&logo=github&color=181717)](https://github.com/glittercowboy/get-shit-done)
+[![GitHub stars](https://img.shields.io/github/stars/gsd-build/get-shit-done?style=for-the-badge&logo=github&color=181717)](https://github.com/gsd-build/get-shit-done)
 [![License](https://img.shields.io/badge/license-MIT-blue?style=for-the-badge)](LICENSE)
 
 <br>
@@ -150,7 +150,7 @@ npx get-shit-done-cc --all --global      # すべてのディレクトリにイ
 リポジトリをクローンしてインストーラーをローカルで実行します：
 
 ```bash
-git clone https://github.com/glittercowboy/get-shit-done.git
+git clone https://github.com/gsd-build/get-shit-done.git
 cd get-shit-done
 node bin/install.js --claude --local
 ```
@@ -810,11 +810,11 @@ OpenCode、Gemini CLI、Codexは `npx get-shit-done-cc` でネイティブサポ
 
 ## スター履歴
 
-<a href="https://star-history.com/#glittercowboy/get-shit-done&Date">
+<a href="https://star-history.com/#gsd-build/get-shit-done&Date">
  <picture>
-   <source media="(prefers-color-scheme: dark)" srcset="https://api.star-history.com/svg?repos=glittercowboy/get-shit-done&type=Date&theme=dark" />
-   <source media="(prefers-color-scheme: light)" srcset="https://api.star-history.com/svg?repos=glittercowboy/get-shit-done&type=Date" />
-   <img alt="Star History Chart" src="https://api.star-history.com/svg?repos=glittercowboy/get-shit-done&type=Date" />
+   <source media="(prefers-color-scheme: dark)" srcset="https://api.star-history.com/svg?repos=gsd-build/get-shit-done&type=Date&theme=dark" />
+   <source media="(prefers-color-scheme: light)" srcset="https://api.star-history.com/svg?repos=gsd-build/get-shit-done&type=Date" />
+   <img alt="Star History Chart" src="https://api.star-history.com/svg?repos=gsd-build/get-shit-done&type=Date" />
  </picture>
 </a>