feat: Add Phase 2 newsletter enhancements and email templates
Phase 2 Implementation:
- Add RSS feed discovery links to footer (Subscribe section)
- Create email templates (base-template.html, research-updates-content.html)
- Add comprehensive newsletter sending implementation plan
- Fix CSP check to exclude email-templates directory
Email templates use inline styles for cross-client compatibility
(Gmail, Outlook, Apple Mail) and are excluded from CSP checks.
Next steps: Install dependencies (handlebars, @sendgrid/mail),
implement EmailService, controller methods, and admin UI.
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>
7d635bf3dc