Archives v1.3 milestone (Phase 13: 18 rclone backends), updates PROJECT.md
with all 30 validated requirements, reorganizes ROADMAP.md with all 4 milestones
in collapsed details blocks, adds v1.2 and v1.3 retrospective entries.
Also commits minor CSS token fixes in src/ (text-on-surface-container class
alignment) that were uncommitted from phase 13 execution.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
- EXPECTED_BACKENDS now includes onedrive, sftp, gcs, b2 (7 total)
- Added describe blocks for OneDrive, SFTP, GCS, Backblaze B2 field assertions
- 9 tests fail RED because registry.ts still has only 3 BackendType values