Two distribution defects left installed skills stale (issue PeterGuy326#8):
1. skill setup resolved its source from cwd / exe-adjacent checkouts, so
an upgraded binary happily re-installed whatever stale checkout it was
run from, and agents kept routing 'create robot' into the chat dead end.
The skills/mono and skills/multi trees are now embedded (go:embed) and
setup defaults to that copy, materialized into ~/.dws/skills/<mode> —
upgrading the binary upgrades what setup installs. --source and
DWS_SKILL_SOURCE stay as explicit overrides, and an override that has
no skill root errors out instead of silently falling back.
2. dws upgrade's skill refresh (knownSkillDirs) skipped ~/.qoder and
~/.qoderwork, so Qoder/QoderWork hosts never got refreshed routing.
Added both to the dir table and its seven mirrors (npm install.js,
install.sh/ps1, install-skills.sh, homebrew template, package test,
verify-package-managers.sh).
setup-side detection and --target qoder/qoderwork already work on this
branch; this closes the remaining upgrade-side and source-side gaps.
