Premirror

Type: page-layout editor reference

Premirror is the strongest future-facing reference for paged editor layout.

Why it matters

• keeps document truth in ProseMirror
• moves measurement and composition into distinct derived stages
• proves page-layout work should not be welded into overlay semantics

Strongest local evidence

• ../premirror/README.md

Limits

• not the main reference for comments/annotations ownership
• relevant for layout and invalidation discipline more than for public overlay API shape