A notebook opens in its own order

The hand-made order is where a notebook's own arrangement lives:
separators show, rows can be put where they belong, nothing slides about
by itself. Starting in "last changed" made both of those look broken
until the sort menu was found — pressing "+ Separator" there drew a line
the order cannot display, so the button appeared dead. A notebook nobody
has arranged still reads newest-first, because untouched rows all carry
position 0, so nothing is lost by starting there. The views keep "last
changed": they are questions asked of every notebook at once and have
nowhere to keep an arrangement. The button that draws a line is now only
offered in the order that can show one.

Removing a chapter left you stuck in the confirmation. Every destructive
action goes through one helper that takes the question down again; this
one set the dialog directly and bypassed it, so the chapter was removed
and the prompt stayed over the app. Closing now happens where the dialog
is rendered, so it happens whoever asked and however they asked.

The suites did not catch that, and the reason is worth keeping: they
read the list straight through the overlay, which is in the DOM the
whole time, and passed while the screen was in fact stuck. Both now
assert the question is gone afterwards.

The separator is no wider than its name. It sat in a fixed 132px slot —
chosen so the row would not jump when renaming began — with a short name
floating in a gap it did not fill.

Thirteen suites green: 345 browser checks, 241 unit tests.

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

frontend/src/features/notes/noteSort.ts

@@ -14,6 +14,23 @@
 
 import type { Chapter, NoteMeta, Separator, SortMode } from "../../types";
 
+/**
+ * What a notebook is in until it is told otherwise.
+ *
+ * The hand-made order, because that is where a notebook's own arrangement lives:
+ * separators show, rows can be dragged into place, and nothing slides about on
+ * its own. A notebook that has never been arranged loses nothing by it —
+ * untouched rows all carry position 0 and fall back to newest first, which is
+ * what the old default showed.
+ */
+export const DEFAULT_NOTEBOOK_SORT: SortMode = "manual";
+
+/**
+ * What a *view* is in — "All Notes", "Starred", the bin.
+ *
+ * Not the hand-made one: those are questions asked of every notebook at once, so
+ * there is nothing for an arrangement to belong to and nowhere to keep it.
+ */
 export const DEFAULT_SORT: SortMode = "updated";
 
 export const SORT_LABELS: Record<SortMode, string> = {