Fix broken links and add missing integration guides GitHub wikis are flat and links must drop the .md extension. - Rewrite all internal links: drop .md, flatten integration-guides/ paths - Add 7 missing integration guide pages from current/docs/integration-guides/ (overview as Integration-Guides; tier guides as integration-guides-<name>) Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>