docs: add Qiita article templates for Watch/Stars requests

[Copilot]

Created comprehensive templates for requesting GitHub Watch/Stars in Qiita articles, with direct links and effective messaging patterns.

Files Added

• docs/etc/QIITA_QUICK_REFERENCE.md - Copy-paste ready minimal templates (Japanese/English)
• docs/etc/QIITA_WATCH_STARS_TEMPLATE.md - Full Japanese templates with 6 patterns
• docs/etc/QIITA_WATCH_STARS_TEMPLATE_en.md - Full English templates with 6 patterns
• docs/etc/README.md - Navigation guide for etc directory

Template Patterns

1. Simple & Friendly (recommended baseline)
2. Value Proposition (emphasizes benefits)
3. Community Participation (engagement focus)
4. Casual & Short (minimal text)
5. Technical Details (engineer-oriented, OSS contribution)
6. Bilingual (Japanese/English mixed)

Key Links

Watch: https://github.com/BonoJovi/KakeiBonByRust/subscription
Star:  https://github.com/BonoJovi/KakeiBonByRust

Example Template

## 📢 プロジェクトを応援してください！

- **⭐ Star**: [リポジトリ](https://github.com/BonoJovi/KakeiBonByRust)右上のStarボタン
- **👀 Watch**: [こちら](https://github.com/BonoJovi/KakeiBonByRust/subscription)から通知設定

あなたの⭐と👀が、開発の励みになります！

Templates include DO/DON'T guidelines, effectiveness measurement tips, and customization examples for different article types (tutorial, bug fix, technical explanation).

Original prompt

Copilotさん、少し教えてください。Qiitaの記事に、Watch/Starsのクリックをお願いする文を挿入しようと思うのですが、どのような文が効果的かというのと、実際のWatch/Starsへのリンクを教えてください！

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