2.23.1

This patch release fixes harness init --template codegem and adds a CodeGem recommended models guide.

Added

• A CodeGem recommended models guide (docs/advanced/codegem-models.md) that
  helps you choose a Gemini or Gemma model and gives a starting configuration
  for each.

Fixed

• superqode harness init --template now accepts every registered template,
  including codegem. The choices were a hardcoded list that had fallen behind
  the template registry; they are now derived from it.