In bash with 'set -u', an undefined variable triggers an unbound-variable
error. Functions don't satisfy '$FUNCNAME' expansion under set -u, so
the previous fix that kept '$PKG_INSTALL pkg...' as the call syntax
broke every call site:
docker.sh: line 53: PKG_INSTALL: unbound variable
Fix: drop the leading '$' in all 47 call sites across 6 generator
files. 'PKG_INSTALL pkg...' is a normal command/function lookup and
behaves identically under set -u or not.
Verified: web UI served docker.sh now has 'PKG_INSTALL' (no $);
'bash -n' passes; smoke run with stubbed PATH hits real line-53 call
site, mock apt-get receives correct args, exit 0, no unbound variable.
Sampled 6 other generators also syntax-OK with $PKG_INSTALL count 0.