Repo-level default override setup #89

Summary

compozy setup already installs skills and global reusable agents, but it could also offer an optional repo-level step to override execution defaults and save them to .compozy/config.toml.

Why

Compozy already has built-in defaults, so users do not need a config file for normal execution. The value here is convenience: setup can give users a guided way to change those defaults and save them to the repo without editing TOML by hand.

The README already documents workspace config and gives a concrete [defaults] example:

[defaults]
ide = "codex"
model = "gpt-5.4"
reasoning_effort = "medium"

That makes setup the natural place to ask whether the user wants to override the built-in defaults for this repo and save those choices automatically.

Right now the flow is:

• Compozy uses built-in defaults automatically
• the README explains how to override them in .compozy/config.toml
• users who want repo-specific defaults still have to create or edit that file manually

An optional setup step would reduce friction for that manual step.

Proposed Behavior

During interactive compozy setup:

• after agent/skill selection, ask whether to override repo-level runtime defaults
• default that answer to No
• if the user opts in, write the chosen overrides to .compozy/config.toml in the current workspace only
• do not prompt for this during compozy setup --global
• do not write config if setup installation fails

Suggested fields for the first version:

• defaults.ide
• defaults.model
• defaults.reasoning_effort

Recommendation Details

• ide should be selected from the supported runtime list
• model should be recommended from the existing per-IDE runtime default mapping
• reasoning_effort should use the same built-in default already used by runtime config

Expected Outcome

Users can finish setup with either:

• no repo config changes, and Compozy keeps using its built-in defaults
• or repo-specific overrides saved to .compozy/config.toml without editing the file manually

That keeps setup aligned with the current README and preserves the existing workspace-only config model.

Notes

• This should stay workspace-scoped. Global setup should not mutate repo config.
• Explicit CLI flags should still override config as they do today.