Function ocrPdf

ocrPdf(vault: Vault, args: OcrPdfArgs): Promise<OcrPdfResult>
Run Tesseract OCR over a PDF's page bitmaps — the image-only / scanned counterpart to readPdf.

When readPdf returns has_text: false, the PDF is image-only; this function renders each page via @napi-rs/canvas and runs Tesseract over the bitmap. Tesseract.js + @napi-rs/canvas are optionalDependencies — without them the function surfaces a clean install-hint error rather than crashing. Costs ~1-3s/page on a modern laptop at default scale.
Parameters
- vault: Vault
  The vault.
- args: OcrPdfArgs
  OcrPdfArgs. path required.
Returns Promise<OcrPdfResult>
An OcrPdfResult with per-page text, confidence scores, and aggregate statistics.
Throws
If path is empty / missing / excluded, or the OCR optional deps aren't installed.

Throws
If path resolves outside the vault.
Example
```
const r = await ocrPdf(vault, {
  path: "Papers/scanned-1978.pdf",
  lang: "eng+fra",
  pages: [1, 10],
  scale: 3
});
console.log(`OCR confidence: ${r.mean_confidence}/100`);
```
- Defined in tools/media.ts:698