Custom <tag name=...> definitions have no scope levels the way variables
do - __tag.cpp always registers into the single global.tags map regardless
of where in the script the definition sits, so this is one flat list, not
broken out by global/local/parent like the existing variable/keyword
sections. Verified end-to-end via a real jet-2.0 run: two tags defined
before <dump> both appear correctly in the DEFINED TAGS section.