* New core/export_github.py producing .alexandria/ backup, human-readable
  wiki/ projection with title-slug filenames + per-folder READMEs + resolved
  raw links, and journal/ with monthly ingest timeline cross-linking wiki
  pages and raw sources
* Wire --format github into the export CLI; include counts in output
* Switch scripts/vault/alexandria-vault-sync and the docs guide to the new
  format so phone-browsable GitHub layout is the default
* Tests covering three-layer output, link rewriting, and footnote dedup
* Bump version to 0.33.0