Add docs for the new concept release system:
- concept_cycle.rst: Technical documentation explaining the release
mechanism, schedule calculations, and troubleshooting guide
- concept_releases.rst: Auto-updated release history file with
installation instructions and real-time schedule generation
- Updated index.rst to include both new documentation files
The documentation covers:
- Bimonthly release schedule (Feb, Apr, Jun, Aug, Oct, Dec)
- RC numbering system counting backwards from final releases
- Dead period handling for dates too early in cycle
- Snap package distribution via Ubuntu Store
- Automated release tracking and history
Co-developed-by: Claude <noreply@anthropic.com>
Signed-off-by: Simon Glass <sjg@chromium.org)
d5ba460e73