Location sharing sent only a legacy geo_uri with a "Location: geo:..." body, so
other clients often rendered it as plain text. Include the MSC3488 blocks
(org.matrix.msc3488.location/asset/ts + m.ts) alongside geo_uri and a readable
body, so Element and others render a proper location pin. Local rendering is
unchanged (still reads geo_uri).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>