Skills installed via Paseo desktop never updated after first run, so
users were stuck on already-fixed skill content. On every launch, if
the paseo base skill is present in `~/.agents/skills/`, sync each
bundled skill (incl. `references/`) into agents, claude (via symlink/
junction), and codex — overwriting only files whose content differs.
Files on disk that are not in the bundle are left alone; deprecation
goes through tombstones (e.g. `paseo-orchestrate` redirects to
`paseo-epic`).
Also refreshes the bundled skill set: drops `paseo-chat`, adds
`paseo-advisor` and `paseo-epic`, and turns `paseo-orchestrate` into
a tombstone redirecting to `paseo-epic`.
Adds a desktop test job to CI on Ubuntu and Windows so the
junction/symlink path is exercised on both platforms.