Update documentation for RSS support

[guglielmo]

Description

Update project documentation to reflect new RSS functionality, including configuration examples, best practices, and troubleshooting.

Tasks

• Update README.md with RSS examples
• Add RSS section to docs/configuration.md
• Document feed auto-discovery feature
• Add examples for common RSS sources (YouTube, Reddit, blogs)
• Document token savings for RSS vs HTML sources
• Add troubleshooting section for feed issues
• Update CHANGELOG.md
• Add migration guide for existing users

Documentation Sections

README.md Updates

• Add "RSS Feed Support" feature bullet
• Add example RSS sources in configuration section
• Add performance comparison (RSS vs Jina)

Configuration Examples

# Direct RSS feeds
sources:
  - https://news.ycombinator.com/rss
  - https://lobste.rs/rss
  
# Blog homepage (auto-discovers feed)
sources:
  - https://blog.example.com
  
# YouTube channel feed
sources:
  - https://www.youtube.com/feeds/videos.xml?channel_id=CHANNEL_ID

Troubleshooting

• Feed not detected
• Malformed feed errors
• Auto-discovery not finding feeds

Acceptance Criteria

• All documentation is accurate and tested
• Examples work as documented
• Links are valid
• Markdown properly formatted
• Screenshots updated if needed

Estimate

Effort: 1 hour
Start Date: 2025-11-18
End Date: 2025-11-19

Dependencies

• Blocked by: Add integration tests with real RSS feeds #21 "Add integration tests with real RSS feeds"

Related

Part of RSS Integration (Hybrid Approach) - Phase 3: Testing & Polish