[Request]: Allow users to set a persistent default mode for --progress (non-BuildKit)

### Feature or enhancement request details

### Description

Following discussion in PR https://github.com/apple/container/pull/899#issuecomment-3619436704 and feedback from maintainers, it would be useful to allow users to configure a persistent default for the --progress flag outside of BuildKit environment variables(https://github.com/apple/container/issues/915).

### Present state:

BuildKit color behavior can be influenced by standard env vars (see #915).

For non-BuildKit operations, --progress defaults are fixed and must be passed explicitly each time.

System properties are based on user defaults, but can be done by potentially migrating these to environment variables so users can set global defaults in shell profiles (e.g., ~/.zshrc, ~/.bashrc) or config files(in ~/.config/container).

### Requested Enhancement

once #899 is merged Add support for a persistent default value for --progress (e.g., plain, color, ansi) using one of the following:
A dedicated environment variable or a system property that can be stored as a global default.
This would allow users to specify their preferred progress mode once globally, while still being able to override it per invocation.

### Code of Conduct

- [x] I agree to follow this project's Code of Conduct

Start by reviewing PR #899 and issue #915, then trace how non-BuildKit operations currently resolve the --progress default. Define a persistent default mechanism and verify that an invocation-level --progress value still overrides it.

Written by the indexing model from the issue text.