Two pnpm workspaces (root globs pcbjam-shared; pcbjam/web has it too) each install yjs, so shared's collab code (kicad-y) and the app's yjs were two physical copies → a Y.Map rejects the other instance's Y types ('Unexpected content type'). resolve.dedupe:['yjs'] in vite + vitest forces a single copy. Not a test-only artifact: the same two copies bundle into the editor and would break collab on doc seed. Full standalone suite now 55/55 (was 47/55).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>