Add OCR language override setting

Operators can now choose Tesseract language pack(s) per profile via a
sidebar select (#optOcrLang) and profile editor (#peOptOcrLang). Presets:
dan+eng (default), dan, eng, dan+eng+deu, dan+eng+swe, dan+eng+fra. The
ocr_lang option flows from the UI through all three scan engines (M365
files/attachments, Google Drive, Gmail) down to document_scanner.scan_pdf
and scan_image — including the spawned PDF-OCR subprocess worker.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

CHANGELOG.md

@@ -11,6 +11,8 @@ Version numbers follow [Semantic Versioning](https://semver.org/spec/v2.0.0.html
 
 ### Added
 
+- **OCR language override** — a new `ocr_lang` scan option (sidebar select `#optOcrLang`, profile editor `#peOptOcrLang`) lets operators choose the Tesseract language pack(s) used when scanning scanned PDFs and images. Presets: `dan+eng` (default), `dan`, `eng`, `dan+eng+deu`, `dan+eng+swe`, `dan+eng+fra`. The setting flows from the UI through the profile, into all three scan engines (M365 `_scan_bytes_timeout`, M365 attachments `_scan_bytes`, M365 files `_scan_bytes`, Google `_scan_bytes` for both Gmail and Drive). The `lang` parameter is threaded through `cpr_detector._scan_bytes` → `document_scanner.scan_pdf` / `scan_image` and the spawned PDF-OCR subprocess worker. The OCR cache key already included `lang`, so per-language results are cached independently.
+
 - **Built-in file redaction for local files** — a scissor button (`✂`) appears on cards for local DOCX, XLSX, CSV, and TXT files. Clicking it rewrites the file in-place with all detected CPR numbers replaced by `██████-████` (DOCX/XLSX) or `█`-blocks (CSV/TXT), then removes the card from the grid and logs a `"redacted"` disposition. The redaction is atomic: a temp file in the same directory is written first and then moved over the original, so a crash never leaves a half-written file. Implemented in `routes/export.py` (`POST /api/redact_item`) using the existing `document_scanner` redact functions; front-end in `results.js` (`redactItem`) with the button hidden for non-local or unsupported-extension items and for resolved/viewer-mode cards.
 
 - **`DELETE /api/delete_item` route registration fix** — the `delete_item` handler in `routes/export.py` was missing its `@bp.route` decorator, so the endpoint was never registered in Flask's URL map. The route now works correctly.