One dialog per thing, and rows dragged into a chapter

A separator had three menu entries — rename, colour, line — plus an input
that appeared in the row itself: three shapes of interaction for one small
thing, and none of them showed the result. Choosing "dotted" from a list
of words is a guess. It is one Edit now, and the dialog draws the line as
it will look with every shape drawn beside its name, from the very rules
the list draws with: a sample that can disagree with the result is worse
than none.

A chapter goes the same way — name, mark and colour in one dialog, the
same one whether it is being made or changed, with the row drawn at the
top. Asked from three entries, getting a new chapter to look right took
three visits. The name dialog it used is gone.

A row is put into a chapter by dragging it onto it: the chapter lights
up and takes what is dropped rather than growing a line above it, since
a chapter is a place and not a neighbour. Notes and separators both, and
the "+ Separator" inside a chapter goes with it — a second way to make
the same thing in a second place is a second thing to keep straight.

A link now wears the mark of the note it points at, in the text and in
the @ menu. It travels when the note's mark changes, as the label
already did.

Two alignment faults: a task list's checkbox was nudged down by a fixed
0.35em measured once against one font, so it floated above the line it
belonged to — it is centred in a box one line tall now. And the title
bar's mark was spaced like the buttons at the far end and grew with its
contents, so picking an emoji shifted the title sideways.

Fourteen suites green: 374 browser checks, 241 unit tests.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

CHANGELOG.md

@@ -8,6 +8,39 @@ not from the output of `docker push`.
 
 ---
 
+## 2026-08-17 — One dialog per thing, and rows dragged into a chapter
+
+**Images** — web `sha256:…`, server unchanged in substance
+
+**Changed**
+- **A separator has one *Edit*** instead of rename, colour and line as three
+  entries — and the dialog **draws the line as it will look**, with each of the
+  five shapes drawn beside its name. Choosing "dotted" from a list of words was a
+  guess. The preview is built from the very rules the list draws with; a sample
+  that can disagree with the result is worse than none. Renaming in the row
+  itself is gone with it.
+- **A chapter likewise**: name, mark and colour in one dialog, the same one
+  whether it is being made or changed, with the row drawn at the top. Asked from
+  three menu entries, getting a new chapter to look right took three visits.
+- **A row is put into a chapter by dragging it onto it.** The chapter lights up
+  and takes what is dropped, rather than growing a drop line above it — it is a
+  place, not a neighbour. Notes and separators both. The **"+ Separator" inside
+  a chapter is gone**: a line is drawn in the notebook and dragged in.
+- **A link wears the mark of the note it points at**, in the text and in the
+  `@` menu, instead of the same sheet-of-paper glyph for everything.
+
+**Fixed**
+- **A task list's checkbox sat above the line it belonged to.** It was nudged
+  down by a fixed `0.35em`, measured once against one font at one size. It is
+  centred in a box exactly one line tall now, which holds at every size and for
+  tasks that wrap.
+- **The title bar read as crooked.** The mark was a child of the header and got
+  the same spacing as the buttons at the far end, so it looked like a control
+  parked beside the title; and the box grew with its contents, so choosing an
+  emoji shifted the title sideways. Mark and name are one group in a fixed box.
+
+---
+
 ## 2026-08-16 — Marks, lines, and a table that breaks
 
 **Images** — web `sha256:1f9f5141…`, server `sha256:3b2f8b44…`