docs: Add partnership outreach email templates

Created comprehensive email templates for strategic partnerships and promotion:

Partners included:
- LangChain (integration opportunity)
- Anthropic (Claude-powered framework)
- Microsoft VS Code (extension integration)
- Hugging Face (model hub integration)
- PyPI Blog (feature request)
- Python Software Foundation (PyCon, education)
- Real Python (tutorial pitch)
- Indie Hackers (building in public story)
- Hacker News (Show HN post)

Each template includes:
- Appropriate subject line and recipient
- Value proposition specific to partner
- Concrete integration opportunities
- Proof points and metrics
- Clear call-to-action
- Example code where relevant

Includes timing recommendations and sending tips.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <[email protected]>

Author: GeneAI