## Why
The plugin and skill test suites were excluded wholesale on Windows, even though
most cases do not depend on POSIX behavior.
## What changed
- Make generated TOML and JSON fixtures escape Windows paths correctly.
- Use Windows-safe path canonicalization and normalize advertised skill paths.
- Select test environments through the environment-aware builders.
- Run the suites on Windows while narrowly skipping cases that execute POSIX
commands or require matching host and executor path conventions.
GitOrigin-RevId: aadf31013c2bf9bac728adc4dd96f572d4a3bf3f
## What changed
- Define skill config selectors, ordered rules, and layer-stack parsing in `codex-config`.
- Resolve disabled skill paths from generic skill name/path pairs, so configuration logic no longer depends on `SkillMetadata`.
- Update plugin and host skill consumers to use the `codex-config` API and consolidate the rule tests with the skill config tests.
GitOrigin-RevId: 3fe67869708df2652befe28d58cdeba933256f84