Editable descriptions and a file tree

A skill's description belongs to whichever version its release tag points at, so it moves when you ship. The rest of this release is about reading a skill once it is published.

Highlights

• Descriptions follow the release tag. Publishing a version that takes latest updates the description shown in registry listings, in search results and on the skill page, so correcting one means shipping a new version rather than editing a published one. A prerelease or a channel-tagged publish leaves it in place, as does a release awaiting review until a reviewer moves the tag onto it.
• Packed files browse as a tree. The Files tab shows a version's full path hierarchy, with folders that expand and collapse and keyboard navigation through them. Two files that share a name under different folders read as the separate entries they are. The list scrolls in its own pane, so the tabs and the sidebar stay in view however many files a skill packs.
• Descriptions in any YAML form. A description written as a folded or literal block scalar renders as its text on the skill page, which is the shape a long description usually takes.
• Sync names the directories it changes. skillhub sync reports the agent directory entries it creates and removes, in its summary and in the --json payload, and warns when the resolved agent set is narrower than the one a skill was installed for. Pass --agent to set the fan-out for a single run, or config set agents to change it for good.