ROADMAP: progress-log line for the spread spine line (#1838)

ROADMAP.md

@@ -380,6 +380,7 @@ list) · [roadmap.md](docs/roadmap.md) (milestones, plan) · [parity-checklist.m
 
 Newest first.
 
+- **2026-10-29** · Spreads show a spine line where their pages meet, on the canvas only (it isn't printed or exported), so the binding edge of a facing-pages spread is visible while laying out across it; right-to-left spreads and pages of different sizes put it on the edge the two pages share (#1838). No readiness percentage change.
 - **2026-10-27** · An iconic panel's flyout stays open while you work in the canvas or a text field: Auto-Collapse Iconic Panels is off by default, and preferences saved with it on start with it off. Preferences › Interface › Panels holds the setting next to the column bar's menu item. No readiness percentage change.
 - **2026-10-24** · Column rules run from the top line's ascent to the bottom line's descent, as InDesign draws them, instead of from the top to the bottom of the columns, on screen, in PDF and in PowerPoint export. The top and bottom insets shorten the rule from those lines. Existing documents draw their column rules at the new length. No readiness percentage change.
 - **2026-10-20** · Edit › Keyboard Shortcuts is craft-keymap's shared dialog: commands grouped by menu with Show and Filter, recording that asks before taking a key from another command, undo and redo, named shortcut sets (edits of Default become Custom; an imported set becomes a set of its own), an on-screen US keyboard, InDesign Show Set files reviewed before they apply, JSON export and an HTML summary. ui.json keeps the `shortcuts` map earlier versions read, for the active set. No readiness percentage change.