fix: update jido_signal lock for OTP 29

[mikehostetler]

Summary

• update jido_signal in mix.lock from 2.2.0 to 2.2.1
• remove the now-unused memento lock entry
• keep the existing {:jido_signal, "~> 2.2"} requirement unchanged because it already admits 2.2.1

Hex API confirms jido_signal 2.2.1 was published on 2026-06-02 and no longer lists memento as a dependency.

Closes #293

Verification

• mix deps.get --locked
• mix test
• mix q

Note: local verification ran on Erlang/OTP 28 with Elixir 1.19.5; this PR removes the memento dependency path that caused the reported OTP 29 compile failure.