fix(editor): discard a rich note nobody typed into

[pasichDev]

Fixes #165.

Opening a note in the extended editor is enough to make the editor serialize a document — an empty paragraph, with an id — and emptiness was decided by comparing that string against "[]". So a new note left untouched read as meaningful: closeActivity() skipped the "new empty note → delete" branch, needsSave() actively wrote it, and the note showed up in the list and in the statistics.

What changed

• EditorDocument.hasContent() (new) decides emptiness from the parsed blocks. A block counts as content unless it is a text block whose text is blank; any file reference counts, read through the existing EditorAttachmentBlocks walk, so data.file and data.files[] are both covered. Only the empty paragraph is written without the user asking for it, so a delimiter, a table, or a tool this build cannot read is kept, and an unreadable document is kept rather than discarded. Free of android.*, so the rule is exercised by ordinary JVM tests.
• The attachments check had the same shape of bug. Every extended-editor change writes the parsed attachment list, which is the string "[]" when there are no files, and "the field is not blank" read that as "this note has attachments" — which alone kept the empty note alive even once the document check was right. It now asks Note.isAttachments(), the same method that already decides which editor a note opens in.
• Removed the extended-editor branch in closeActivity() that its own comment called wrong. It is unreachable: needsSave() already requires content.

Behaviour worth knowing about

An existing note the user empties is no longer saved — the stored text stays and the note is not deleted either. That is what the simple editor has always done, and the parity this issue asks for, but it is a change for rich notes, so existingNoteEmptiedByTheUserKeepsWhatWasStored pins it as a deliberate decision rather than an accident.

Tests

17 new unit tests. EditorDocumentTest covers the shapes the issue lists — [], a single empty paragraph, whitespace and empty markup, empty header and list, an attachment as the only content — plus image/gallery blocks, a delimiter, a table, an unknown tool, and an unreadable document. NotePresenterEmptyExtendedNoteTest covers the close path end to end; its two "empty note" tests fail against the old check and pass against the new one.

Full unit suite, lintDebug and spotlessCheck are green.

[github-actions]

Test coverage (unit + instrumentation)

Overall Project	18.23% -0.12%	🍏
Files changed	47.48%	🍏

Module	Coverage
debug	19.65% -0.23%	🍏
debug	16.81% -0.01%	🍏

Files

Module	File	Coverage
debug	EditorDocument.java	0%	🍏
	NotePresenter.java	0% -0.76%	🍏
debug	EditorDocument.java	94.79% -5.21%	🍏
	NotePresenter.java	50.76%	🍏