Compose: say where reuse resumes after an edit that moves lines

An edit that moves lines into other frames composes on until a paragraph
starts in the same frame and place as before, or to the story's end, as
an_edit_that_moves_lines_composes_up_to_the_next_frame_the_text_starts_in
shows. The ROADMAP line no longer cites an issue about selection lag.

ROADMAP.md

@@ -387,7 +387,7 @@ list) · [roadmap.md](docs/roadmap.md) (milestones, plan) · [parity-checklist.m
 
 ## Progress log
 
-- **2026-11-12** · An edit of a long threaded story composes the paragraphs it can change and copies the other lines from the composition before the edit; every typed character composed the whole story. In a 240-paragraph story a typed character composes 3 paragraphs (240 before). An edit that moves lines into other frames is composed to the story's end, and stories with footnotes, tables, anchored objects, balanced columns or keep options that move lines are composed whole (#2298). No readiness percentage change.
+- **2026-11-12** · An edit of a long threaded story composes the paragraphs it can change and copies the other lines from the composition before the edit; every typed character composed the whole story. In a 240-paragraph story a typed character composes 3 paragraphs (240 before). An edit that moves lines into other frames composes on until a paragraph starts in the same frame and place as before, or to the story's end, and stories with footnotes, tables, anchored objects, balanced columns or keep options that move lines are composed whole. No readiness percentage change.
 - **2026-11-04** · Striped strokes retain out-and-back cubic segments whose second control point is away from the coincident endpoints and first control point. A geometry regression checks the offset extent and both stripe bands. No readiness percentage change.
 - **2026-11-04** · Esperanto is a text language (Character › Language, `type.char {language: "Esperanto"}`, IDML `$ID/Esperanto`): tag `eo`, English-style quotes; not hyphenated yet (#1201). No readiness percentage change.
 

docs/architecture.md

@@ -74,7 +74,8 @@ revision; stories compose in parallel (rayon) on native targets. After an edit o
 or formatting, composing starts at the paragraph before the first changed one and stops at the
 first unchanged paragraph it reaches in the state it had before the edit; the lines above and
 below are copied from the composition before the edit (`crates/compose/src/reuse.rs`). An edit
-that moves lines into other frames is composed to the story's end. A story is composed whole
+that moves lines into other frames composes on until a paragraph starts in the same frame and
+place as before, or to the story's end. A story is composed whole
 when it has footnotes, endnotes, tables, anchored objects, named lists, tracked deletions,
 balanced columns, vertical justification other than Top, column rules, type on a path, spanning
 or split paragraphs, or paragraph borders or shading, and when its layout goes back over a