Copy OCR text as paragraphs

A Paragraphs toggle (Ctrl+J, on by default) makes copied and saved text
put each paragraph on one line: line breaks inside a paragraph become
spaces and words hyphenated across lines are rejoined (the hyphen stays
before a capital, as in "Nord-Amerika"). A line ends its paragraph if the
next one is indented, has a different text size, or starts with a word
that would have fitted at the end of this one, which works for justified
and ragged-right text alike; rows of several items (tables) are left
alone. The right-click menu offers the other form.

ocr.paragraph_joins gives the joins as edits on layout()'s text, and
reflow applies those inside any range, so selections keep working on the
page's character positions.

Ctrl+C now copies in the chosen form (QAction.triggered passed
checked=False through as paragraphs=False), and tabs show in the status
bar's selection preview.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

README.md

@@ -24,7 +24,11 @@ Linux driver tools for the Hama myScan (00052343) scanner mouse, a Dacuda design
   multilingual PP-OCRv6 models bundled in the wheel, works offline). Recognised lines are outlined on the page by
   confidence, and the text is selected right on the page like in a PDF viewer: drag (in reading order across
   lines), double-click a word, triple-click a line, shift-click to extend, Ctrl+A; Ctrl+C or right-click copies.
-  Middle-drag or Space+drag pans, the wheel zooms. Copy all and Save text (.txt) take the whole page. `python tools/app.py [image]` also opens and reads existing images (Open, or
+  With Paragraphs on (Ctrl+J, the default), copied and saved text has each paragraph on one line:
+  line breaks inside a paragraph become spaces and words hyphenated across lines are rejoined; a line ends a
+  paragraph if the next line is indented or its first word would have fitted on it (works for justified and
+  ragged text), and rows with several columns are left alone. Right-click offers the other form. Middle-drag or
+  Space+drag pans, the wheel zooms. Copy all and Save text (.txt) take the whole page. `python tools/app.py [image]` also opens and reads existing images (Open, or
   drag and drop), which is all it does on machines without the mouse
 - `myscan/scanner.py` — the scan loop shared by `scan.py` and the app (finds the mouse's `/dev/videoN` itself)
 - `myscan/live.py`, `myscan/webview.py` — the live preview and its browser viewer (standard library only)