Quarantine or remove unused files without breaking installer

[fcimeson]

Goal

Reduce repo clutter over time by removing or quarantining unused files, without breaking profiles or install.sh lookups.

Scope

• Identify unused/legacy files and directories
• Prefer quarantining (move to _archive) when uncertain
• Update registry.json/install paths if needed

Acceptance criteria

• Installer profiles still succeed after cleanup
• No broken references in registry.json/docs
• Clear rationale documented for removed/quarantined items