- Moved examples/generate.py to betaearth/generate.py so it ships with the
  PyPI package (was previously only usable from a repo checkout)
- Added 'betaearth-generate' CLI entry point in pyproject.toml
- Added --no_per_timestamp_embedding flag so annual-only runs are easy
- Enhanced manifest: generated_at, model info (repo + betaearth version),
  acquisition params, inference params, and per-scene STAC id, collection,
  datetime, platform, S1 orbit/polarisation — full provenance
- Simplified sync-hf-space workflow (no need to copy + sed generate.py now
  that it comes from pip install betaearth[generate])
- README: new 'Generate a custom dataset (CLI)' section
- Space pinned to betaearth[generate]>=0.2.2