docs(agents): plan the layout accuracy programme

[eliahilse]

TL;DR:

Summary:

• adds openspec/accuracy-plan.md, sequencing the Word-fidelity work as measurement first: committed corpus + scorer, a manual AppleScript capture path for goldens, then reproducing the page-count figure, then ranking the residual error before fixing anything
• records the current state verified against main: exact (0.80 baseline ratio, font-independent) and atLeast (slack above the baseline) are already implemented and Word-measured in ooxml-text, and metric quantization is correctly opt-in — so those are not open work
• notes the gap that motivates the plan: the 61.9% exact page-count figure in the fonts README came from a harness that was never committed, so it cannot be reproduced or regressed against
• parks CRDT state caching as an adjacent performance item, now that fix(docx): make story seeding linear by applying raw ops as one delta #217 made the first open linear

Test plan:

• docs only — no code paths touched

[openooxml-bot]

All contributors have signed the CLA — thank you! ✍️ ✅

_{Posted by the CLA bot.}

[greptile-apps]

Greptile Summary

This documentation-only PR adds a measurement-first programme for improving Word layout fidelity.

• Defines committed corpus, deterministic golden, scoring, and manual Word-capture phases.
• Records already-implemented line-spacing and metric behavior.
• Separates future CRDT state caching from layout-accuracy work.

Confidence Score: 5/5

The PR appears safe to merge because it changes documentation only and no concrete inaccurate or harmful guidance was identified.

The plan accurately frames the missing benchmark harness, current layout behavior, proposed measurement phases, and adjacent CRDT caching work without changing runtime behavior.

Important Files Changed

Filename	Overview
openspec/accuracy-plan.md	Adds a coherent accuracy roadmap whose material current-state claims align with repository implementations and documentation; no actionable defect was found.

_{Reviews (1): Last reviewed commit: "docs(agents): plan the layout accuracy p..." | Re-trigger Greptile}