Remove B1/B2 benchmarks and revert Project.toml to avoid Catalyst upgrade

B1 and B2 require SBMLImporter v3 which needs Catalyst v15+, but the
existing Bio benchmarks (BCR, Bidkhori2012, etc.) are written for
Catalyst v14. Widening compat caused CI to resolve Catalyst v15 and
break existing benchmarks.

Revert Project.toml and Manifest.toml to master's versions. B4 and B5
are self-contained (manually coded ODE functions) and don't need
SBMLImporter or Catalyst. B1/B2 will be added in a follow-up PR once
SBMLImporter compatibility is resolved.

Co-Authored-By: Chris Rackauckas <accounts@chrisrackauckas.com>
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: ChrisRackauckas