Put the interface into English, and give the notebook one way in

The interface had drifted into two languages — the frame in English, everything
added later in German — which is worse than either, since the same idea appeared
under two names depending on when that part was written. Sorting by title still
uses the German collation, so Übung 2 comes before Übung 10: that is about the
notes, not the chrome.

Two archive folders were renamed with it (bilder/ → images/, zeichnungen/ →
drawings/). The importer reads both spellings, and both the old and new marker
line for a drawing — archives exported before this are on disk, and an import
that quietly dropped their drawings would be the worst kind of tidy-up.

Making a note, uploading a PDF and importing Markdown were three buttons side by
side, two of them icons you had to hover to identify. They are the same act —
putting something new in this notebook — so they are now one + menu.

The search box moves out of the sidebar and into the note list, labelled with the
notebook it narrows. Nothing changed about what it does: it has always searched
only the notebook you are in, but from the sidebar it read as searching
everything.

A separator no longer carries a sentence explaining the order the sort menu
already names. Renaming joins removing on the right-click menu — a left-click on
the label started an edit, so the row could not be touched without falling into
one.

218 unit tests, 238 browser checks across eleven suites. Two of those caught real
breakage from this change rather than needing a translation.

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

readme.md

@@ -368,6 +368,24 @@ state of their own, so they can be read on their own.
 
 ---
 
+## Interface language
+
+English throughout. It had drifted into two languages — the frame in English,
+everything added later in German — which is worse than either: the same idea
+appeared under two names depending on when that part was written.
+
+The one place German is deliberately kept is sorting by title, which compares
+with the German collation so that *Übung 2* comes before *Übung 10* and umlauts
+sort where a German reader expects. That is about the notes, not the chrome.
+
+Two archive folders were renamed with the interface (`bilder/` → `images/`,
+`zeichnungen/` → `drawings/`). **The importer still reads both**, along with the
+old German marker line for a drawing — archives exported before the change are
+on people's disks, and an import that quietly dropped their drawings would be the
+worst kind of tidy-up.
+
+---
+
 ## Note Content
 
 The body of a note is a **TipTap/ProseMirror document** stored as JSON:
@@ -739,10 +757,11 @@ questions asked of every notebook at once, so there is nothing for an
 arrangement to belong to and nowhere to keep it.
 
 **Separators** are lines drawn between notes, optionally named, stored on the
-notebook beside the sort mode. One is removed by right-clicking it and
-confirming — a × on the row would sit a few pixels from the label you click to
-rename, putting the gesture that tidies the list next to the one that destroys
-part of it. They move by dragging like a note does — a
+notebook beside the sort mode. Renaming and removing are both right-click, which
+is how everything else in that list is acted on: a left-click on the label used
+to start renaming, so the row could not be clicked at all without falling into an
+edit, and the × for removal sat a few pixels from that same target. Removal asks
+first, and says the notes are not affected. They move by dragging like a note does — a
 divider that cannot move with what it divides is worse than none — and their
 position is recorded as "how many notes come before me", so they stay put as the
 notes around them are renamed, edited or opened. They are shown only in the