09ada9c1b5
web/demo.improv has no groups and one category per visible axis, deliberately (gotcha 46), so the multi-level header, the group span, the collapse indicator and the inline group row -- exactly the code improvise-anr9 added -- had never been rendered anywhere a test could see (improvise-plcx). harness/fixtures/grouped.improv is served beside the shipped demo by harness/build.sh; web/demo.improv is untouched. Two categories on each visible axis, three row groups with one collapsed, two column groups. A missing seed is NOT an error -- web/worker.js answers a 404 with an empty model -- so every assertion is about labels the fixture really carries, never that a grid exists. Five injections, five distinct failures, patched in harness/serve so no rebuild stands between the fault and the run: slash-joining the level tuples; colSpan = 1 on the group headers; a stray cell on the inline group row; indicator(false) hard-coded; and the collapse removed from the document. One thing the ticket did not predict: the row frame's FIRST group header is never drawn, so the spec asserts two group rows where the document has three, with improvise-0o6x named on the line. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01FC2jVn8Au7E9JPkw6bwXXH