Eject CLI

## Context After the public Shadcn registry contract is validated, Video.js should provide guided source-installation and Skin-ejection workflows over the same canonical catalog and delivery artifacts. This issue owns Skin-specific CLI outcomes. Generic command infrastructure and future project initialization remain separate under #247. ## Product surface ```sh videojs add skin video videojs add skin video --dry-run videojs add skin video --diff videojs view skin video videojs eject skin video ``` ## Scope - Detect or request the framework and style target. - Resolve source from the canonical catalog and validated registry contract. - Preview files and dependencies before writing. - Support view, dry-run, diff, and explicit overwrite behavior. - Replace recognized packaged Skin usage through narrow, safe transforms. - Preserve packaged Media, Store, state, and feature implementations. - Give complete manual instructions when an automatic replacement is unsafe. ## Acceptance criteria - [ ] React/Tailwind installation uses the same public artifacts as direct shadcn usage. - [ ] Other supported framework/style targets preserve the same catalog item and ownership boundaries. - [ ] Detection either selects a valid target or asks the developer explicitly. - [ ] View, dry-run, and diff do not modify the project. - [ ] Existing files are not overwritten without explicit confirmation. - [ ] Safe replacement transforms are idempotent. - [ ] Unsafe or divergent packaged usage is left unchanged with actionable instructions. - [ ] Clean React and HTML fixture projects build after installation. - [ ] Command output clearly identifies installed files, dependencies, and developer ownership. ## Required context - #1055 - #1951 - #2261 - #247