Notes: edit a text file of any size (#47)

The editor held the whole note in memory and stopped at 16 KB. It now keeps
a window of the file around the cursor, and the rest on the card as a list
of pieces (notes::NoteDocument). Memory with a note open is what it was.

Up to 64 KB a save rewrites the file, as before. Above, the five-second
save appends what changed to <note>.edit, and the file is rewritten on
leaving the note, with a progress bar. After a power cut, opening the note
picks the edit up where it was saved; a rewrite cut short is finished or
dropped, never half applied.

Also: Ctrl with Fn+Up/Down go to the start and end of the note; the
consoles' `key` command takes ctrl-, alt- and shift-; the Storage App's
`e` no longer refuses a big file.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EhqxQ49eCju4CzKYNjZzwT

src/apps/notes_app.cpp

@@ -25,6 +25,10 @@ bool endsWith(const std::string& s, const char* tail) {
     size_t n = std::strlen(tail);
     return s.size() >= n && s.compare(s.size() - n, n, tail) == 0;
 }
+
+// Beside a note, and not one: a save cut short (.tmp), a long note's unsaved edits (.edit), and
+// edits that no longer fit their file, kept for whoever wants to look (.edit.lost).
+bool notANote(const std::string& name) { return endsWith(name, ".tmp") || endsWith(name, ".edit") || endsWith(name, ".edit.lost"); }
 }  // namespace
 
 void NotesApp::onEnter() {
@@ -125,6 +129,7 @@ void NotesApp::onFinished(const FileOps::Status& s) {
             if (list_.find(name.substr(0, name.size() - 4)) < 0) orphans.push_back(name);
             continue;
         }
+        if (notANote(name)) continue;
         notes_.push_back(static_cast<uint16_t>(i));
     }
     if (!orphans.empty() && !mended_) {
@@ -202,6 +207,8 @@ bool NotesApp::onKey(const KeyEvent& e) {
             selectIndex_ = rows_.selected();
             selectAfter_.clear();
             std::string why = ops_.remove(target_, false);
+            std::string side = target_ + ".edit";  // a long note's unsaved edits go with it (issue #47)
+            if (why.empty()) storage_.runJob([side]() { SD.remove(side.c_str()); });
             if (why.empty()) wait_ = Wait::Work;
             else say(why);
         }
@@ -225,6 +232,8 @@ bool NotesApp::onNameKey(const KeyEvent& e) {
             if (why.empty() && name != baseName(target_)) {
                 why = ops_.move(target_, false, joinPath(kFolder, name));
                 if (why.empty()) {
+                    std::string side = target_ + ".edit", sideTo = joinPath(kFolder, name) + ".edit";
+                    storage_.runJob([side, sideTo]() { SD.rename(side.c_str(), sideTo.c_str()); });
                     wait_ = Wait::Work;
                     selectAfter_ = name;
                 }
@@ -268,7 +277,7 @@ bool NotesApp::onListKey(const KeyEvent& e) {
         list_.sort(sort_);
         notes_.clear();
         for (size_t i = 0; i < list_.count(); i++)
-            if (!list_.folder(i) && !endsWith(list_.name(i), ".tmp")) notes_.push_back(static_cast<uint16_t>(i));
+            if (!list_.folder(i) && !notANote(list_.name(i))) notes_.push_back(static_cast<uint16_t>(i));
         for (size_t i = 0; i < notes_.size(); i++)
             if (keep == list_.name(notes_[i])) rows_.select(static_cast<int>(i));
         titlesFrom_ = -1;