Fixes#8609
# Summary
Emphasize single-line name/description values and quoting when values
could be interpreted as YAML syntax.
# Testing
Not run (skill-only change.)
1. Remove PUBLIC skills and introduce SYSTEM skills embedded in the
binary and installed into $CODEX_HOME/skills/.system at startup.
2. Skills are now always enabled (feature flag removed).
3. Update skills/list to accept forceReload and plumb it through (not
used by clients yet).