chore(tommy): regen codegen + fixtures for tommy bump

The flake update bumped tommy. Its encoder now gates emission of empty
TOML arrays on whether the key was present in the source CST, so freshly
encoded configs no longer carry `blob-stores = []` / `tags = []` lines.
This changed the genesis digests for v15 fixtures and the konfig blob
written by `dodder init`.

- Regenerate v15 fixtures (.dodder/, .madder/, .fixtures.env)
- Drop `tags = []` from `dodder show :konfig` assertions
- Rewrite editor sed in 3 tests (`checkin_explicit_workspace_delete_files`,
  `organize_new_objects_default_tags`, `organize_default_tags_workspace`)
  to insert tags after `[defaults]` instead of substituting `tags = []`,
  and update the resulting konfig SHA
- Update hardcoded konfig SHA in `edit_config_and_change`

:clown: Generated with [Clown](https://github.com/amarbel-llc/clown)

Author: friedenberg