* fix: block Podman on macOS and remove ghcr.io default
- Add platform check in PodmanCLI.__init__() that raises FuzzForgeError
on macOS with instructions to use Docker instead
- Change RegistrySettings.url default from "ghcr.io/fuzzinglabs" to ""
(empty string) for local-only mode since no images are published yet
- Update _ensure_module_image() to show helpful error when image not
found locally and no registry configured
- Update tests to mock Linux platform for Podman tests
- Add root ruff.toml to fix broken configuration in fuzzforge-runner
* rewrite guides for module architecture and update repo links
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Co-authored-by: AFredefon <antoinefredefon@yahoo.fr>