Pin LC_ALL=C in any pipeline that compares sorted text with comm/join/diff

A verification gate that compares a reference list against freshly generated output with sort | comm can report thousands of false differences when the reference was sorted in the C locale and the machine running the gate sorts in a UTF-8 locale. Collation differs for punctuation, case and characters like '.', '[' and '_', which are common in hierarchical signal or path names. In one cloud run, a fresh VM's default locale made a byte-identical result fail with ~28k differing rows. Fixes: export LC_ALL=C at the top of every driver and gate script (not only around sort), record the locale in the run log, and when re-checking a failed gate, re-sort both sides with LC_ALL=C before concluding the data differs. A Linux container test of the gate with a non-C default locale catches this before a paid run.