myTODO v1.0.0

docs: GitHub migration, release process and live-update documentation

- README: install section (installer with auto-update vs portable zip),
  maintainer release steps, license
- CLAUDE.md: repo now lives at github.com/lexandro/mytodo (public, explicit
  decision), gitlab kept as backup mirror; release + updater rules and
  signing-key location; command list refreshed
- ARCHITECTURE: live update section; ROADMAP pointer updated
- progress log entries for the afternoon/evening work

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>