Add fixture analysis/split/merge scripts for the D6 restructure,
update aimock fixture collision detection tests for the new directory
layout, update GOTCHAS.md and QA-COVERAGE.md with D6 notes, and
add --d6 flag support to the showcase test CLI.
What we learned getting 18 integrations to D5 green — and what was
still wrong even when green. Cross-framework patterns (V1/V2, testids,
runtime hoisting, agent naming, multimodal shims, Pydantic models),
per-framework edge cases for all 15 frameworks, aimock fixture gotchas,
and the 6 things that were "green but wrong."
Jordan Ritter