Lay the notes screen out like a notes app

The list of notes and the note being written are one screen now, two
panes: the notes on the left, the open one on the right, side by side
where there is room and one at a time on a phone, where the back button
returns to the list.

The search box moved into the top of that list, and its results *are*
the list — searching is a way of finding a note, not a separate place to
be, and a tab for it was a tab too many. Emptying the box brings the
whole list back. Opening a hit opens that day at the lesson that
matched, rather than at the top of a day with six of them.

A row has to say what the note holds, so the listing carries it: the
subjects a day covers, how many lessons, and the first line actually
written in it. One request for the whole list rather than one per note.

`plainText` is now one rule in one place for wherever a note is shown
rather than edited — the search snippet and the list row both went
through their own half-copy of it, and the row's copy rendered a table
as `| | |` and left `_Fazit_` wearing its markers. It strips one leading
marker, not each in turn, because `## 1. Deutsch` keeps its lesson
number and the list rule was eating it.

Driven in Firefox at both widths: the list, the search, opening a hit,
the jump to the lesson, and the phone's list-then-note. 390 unit tests,
116/117 smoke.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

README.md

@@ -86,9 +86,11 @@ teachers, rooms, cancellations dropped and substitutions marked. Each heading is
 indexed as its own lesson, so a search answers "my own note, Deutsch,
 18.09.2026" rather than "Friday".
 
-A **Suche** tab searches your own notes straight from the files — no crawl in
+It reads like a notes app: the notes on the left, the open one on the right, and
+a search box above the list. Search goes straight to the files — no crawl in
 between, so a lesson written this morning is findable this morning — and a
-result names the lesson it matched in rather than the day.
+result names the lesson it matched in rather than the day, opening that day at
+that lesson.
 
 Writing is **formatted, not Markdown**: headings, bold, lists, tick boxes,
 quotes, links and tables come from a toolbar, and `MD` shows the Markdown