feat(ocr): crop + rotate modal before recognition

After picking an image, a modal opens with cropperjs's drag-handle
crop UI and Rotate left / Rotate right / Reset buttons. Cropping
to just the text region is the single biggest quality win for
OCR on phone photos — strips out logos, lighting transitions, and
background junk that bleed past the confidence filter.

- Lazy-loads cropperjs + its CSS from esm.sh on first use (no
  bundling; same pattern as Tesseract.js and CodeMirror).
- Honours EXIF orientation from phone shots (checkOrientation).
- Keyboard: Esc cancels, Enter accepts. Clicking the backdrop
  also cancels.
- Output goes through the existing preprocessForOCR pipeline
  (downscale to 1600px + Bradley adaptive threshold) before
  Tesseract sees it.

CHANGELOG.md

@@ -12,6 +12,7 @@ Versioning: [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 - Images are downscaled to 1600 px on the long edge before OCR. A 12 MP phone photo (~4000 px) drops to ~1.3 MP, making Tesseract 4-8× faster with no real accuracy loss for printed text. Smaller-than-1600 px inputs are passed through unchanged.
 - Adaptive thresholding (Bradley's method with integral images) binarises the downscaled image before OCR — drops hallucinated text from shadows, gradients, and surface texture on phone photos. Output is pure black-on-white, much closer to the scanned-page input Tesseract was trained on.
 - Per-word confidence filter (≥ 60) drops the low-confidence noise Tesseract still emits. Re-assembles lines from kept words; status line reports how many words were dropped.
+- Crop & rotate modal between image pick and OCR. After choosing an image, a modal pops up with cropperjs's drag-handle crop UI and Rotate left / Rotate right / Reset buttons. EXIF orientation is honoured automatically. Cancel / `Esc` / clicking the backdrop aborts; `Enter` accepts. Library lazy-loaded from esm.sh (no bundling).
 
 ### Fixed
 - "Hot: …" status no longer claims "unloads in X" when the server's `keep_alive` is `-1` (Ollama returns an absurd year-4001 `expires_at`). Threshold: any expiry >7 days drops the suffix and just shows the model name.