Cowork plugins: support live-sync from user-managed skill files instead of static cache

Problem

When a user edits a plugin's SKILL.md on disk (e.g., in Dropbox or a local folder), Cowork does not pick up the changes. The plugin system caches a snapshot of each skill at install time into .local-plugins/, and that cached copy is read-only inside the Cowork VM. There is no mechanism to reference an external source file, symlink to a user-managed path, or auto-refresh from the original location.

This means every skill edit requires one of:

1. Manually pasting the updated content into the Cowork UI "Edit" view
2. Re-uploading the entire plugin package

For users who iterate on skills frequently (which is the whole point of customizable plugins), this creates unnecessary friction and a persistent divergence between the "real" skill file and what Cowork actually executes.

Expected Behavior

At least one of the following:

1. Live-sync option: Allow a plugin to reference a local directory (e.g., ~/ClaudeCode_2026/shared/skills/ai-news-digest/) as the source of truth, so Cowork reads the SKILL.md from there at session start instead of from the static cache.

1. Auto-refresh on session start: On each new Cowork session, check whether the source files have changed since the cache was created, and refresh if so.

1. Hot-reload from disk: If the mounted workspace contains a newer version of a cached skill file, prefer the workspace version.

Current Workaround

Edit via the Cowork UI "Edit" button (one skill at a time, no version control, no diff). Or re-upload the .plugin package after every change.

Context

• Plugin structure: plugin.json + commands/*.md + skills/*/SKILL.md — all static, all read-only in the VM
• The .local-plugins/ cache directory is not writable from inside a Cowork session
• Users who maintain skills in version-controlled directories (Dropbox, Git repos) have no way to keep the plugin cache in sync without manual intervention

Environment

• Cowork (Desktop App, macOS)
• February 2026