chore: create measurement to layout ownership matrix

[VladaHarbour]

This PR introduces measuring-layout-ownership.md document with Measuring → Layout ownership matrix and tests which lock current boundary.
@harbournick please let me know if it should live in the repo

[linear]

SD-2845 Define Measuring → Layout ownership contracts across block types

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.

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[caio-pizzol]

direction is right. three things inline.

Inline 1 - packages/layout-engine/docs/measuring-layout-ownership.md, line 1:

new docs/ folder - we keep layout-engine docs in CLAUDE.md and per-package READMEs today. could this go in CLAUDE.md instead? the follow-up list at the bottom feels like a Linear backlog.

Inline 2 - packages/layout-engine/layout-engine/src/measuring-layout-ownership-contracts.test.ts, lines 179-206:

the measuring test covers section breaks but this one only covers page and column breaks. could we add a section break case here too?

inline 3 - packages/layout-engine/layout-engine/src/measuring-layout-ownership-contracts.test.ts, lines 214-242:

this only passes because list layout isn't supported yet - when it lands, the test will start failing. could we use it.todo(...) so the next person updates it instead of deleting?

[VladaHarbour]

direction is right. three things inline.

Inline 1 - packages/layout-engine/docs/measuring-layout-ownership.md, line 1:

new docs/ folder - we keep layout-engine docs in CLAUDE.md and per-package READMEs today. could this go in CLAUDE.md instead? the follow-up list at the bottom feels like a Linear backlog.

Inline 2 - packages/layout-engine/layout-engine/src/measuring-layout-ownership-contracts.test.ts, lines 179-206:

the measuring test covers section breaks but this one only covers page and column breaks. could we add a section break case here too?

inline 3 - packages/layout-engine/layout-engine/src/measuring-layout-ownership-contracts.test.ts, lines 214-242:

this only passes because list layout isn't supported yet - when it lands, the test will start failing. could we use it.todo(...) so the next person updates it instead of deleting?

Hi @caio-pizzol! Added some changes to address your comment

[caio-pizzol]

Thanks for working on this. I’m going to close this PR because it is now out of date with main.

The work is still useful, especially the two test files and the Measuring → Layout notes. But the docs structure changed since this PR was opened, so this now has conflicts and some wording is stale.

The clean path is to open a fresh PR from current main with:

• the two test files
• an updated packages/layout-engine/AGENTS.md section
• no CLAUDE.md changes

Closing as stale, not because the idea is no longer relevant.