go:embed the skills/ tree (mono + multi) into the binary and make
`dws skill setup` install from the embedded bundle by default. Upgrading
the binary now refreshes the installed skill, instead of silently reusing
a stale copy probed from the current working directory. An explicit
--source / DWS_SKILL_SOURCE still overrides for development.
Replants the change from #441 onto main: #441 was stacked on the
abandoned feat/chat-bot-provisioning-openclaw base (PRs #407/#397 closed),
which is why its CI was red. The embedded-bundle test asserted a
connect.md doc that only existed on that dead base; retargeted it to a
reference doc that exists on main.
修雨