Decide text orientation per page instead of per line

RapidOCR's angle classifier judges each cut-out line on its own and now
and then turns a perfectly upright line upside down, which then reads as
garbage ("Jo a ds ne t i d s t d no" for a line ending in "or" on the
latest scan). It is off now. All lines on a page face the same way, so a
page that reads poorly (upright text scores 0.97-1.0 per character,
upside-down text 0.55-0.8) is read again rotated 180 degrees and the
better reading kept; that also covers pages turned 90 degrees. The app
shows an upside-down page turned the right way up.

Upright pages read about 25% faster without the per-line classifier.

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

README.md

@@ -21,7 +21,7 @@ Linux driver tools for the Hama myScan (00052343) scanner mouse, a Dacuda design
   page and a Screenshot button (camera + page + status as one PNG)
 - `tools/app.py` — desktop app (Qt/PySide6; Linux, Windows, macOS): live camera and page view while scanning
   (Start/Stop or the scan button, F5), then OCR of the finished page with RapidOCR (`myscan/ocr.py`;
-  multilingual PP-OCRv6 models bundled in the wheel, works offline). Recognised lines are outlined on the page by
+  multilingual PP-OCRv6 models bundled in the wheel, works offline; an upside-down page is detected and turned). 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.
   With Paragraphs on (Ctrl+J, the default), copied and saved text has each paragraph on one line: