pull all non-essential code out of the on-chain stuff - #640

these 5 derivations will be built:
  /nix/store/rjnzcs9jdxwxbcz020kqbxpgbv0n5ngp-Cargo.toml.drv
  /nix/store/yi0jpwv101bcfr5cc5ghlqlw8nidjn92-source.drv
  /nix/store/c3p5dl4q5djdrrah9kfsyrlq58h8mw6g-psyche-workspace-deps-0.2.0.drv
  /nix/store/kb2zmrvcbdkdfqx2nr087mv6i7cmpzp2-psyche-centralized-server-0.2.0.drv
  /nix/store/2prmp5bh7i6jzjyvi7dhcipb2ni1xg52-validate-configs.drv
validate-configs> Note: client has no state.toml, skipping validation
validate-configs> checking consilience/state.toml
validate-configs> 2026-03-24T20:56:43.594964Z ERROR psyche_centralized_server: Error found in config: TOML parse error at line 20, column 2
validate-configs>    |
validate-configs> 20 | [model.LLM]
validate-configs>    |  ^^^^^
validate-configs> missing field `max_seq_len`
validate-configs> 
error: build of '/nix/store/2prmp5bh7i6jzjyvi7dhcipb2ni1xg52-validate-configs.drv' on 'ssh-ng://nix-ssh@garnix8' failed: builder for '/nix/store/2prmp5bh7i6jzjyvi7dhcipb2ni1xg52-validate-configs.drv' failed with exit code 1;
       last 8 log lines:
       > Note: client has no state.toml, skipping validation
       > checking consilience/state.toml
       > 2026-03-24T20:56:43.594964Z ERROR psyche_centralized_server: Error found in config: TOML parse error at line 20, column 2
       >    |
       > 20 | [model.LLM]
       >    |  ^^^^^
       > missing field `max_seq_len`
       >
       For full logs, run 'nix log /nix/store/2prmp5bh7i6jzjyvi7dhcipb2ni1xg52-validate-configs.drv'.
error: builder for '/nix/store/2prmp5bh7i6jzjyvi7dhcipb2ni1xg52-validate-configs.drv' failed with exit code 1