fix: keep `@[grind inj]` theorems in `grobner [...]`

Use the default `@[grind]` extension state with only its E-matching rules cleared, rather than the `only` state, so injectivity theorems remain available when a parameter list is given.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
3 files changed