fix: landing page Unicode rendering, orbit overlap, and add PDF OCR fallback

- Fix Unicode escapes (\u26A1, \u2192, \u{1F6E1}) rendered as literal text in JSX
  by wrapping them in JSX expressions
- Increase orbit radii (520/320px -> 720/480px) so items don't overlap hero text
- Add orbit animation keyframes (orbit-slow, orbit-med) to globals.css
- Add Tesseract.js OCR fallback for scanned/image-based PDFs that have no
  extractable text layer — renders pages to canvas then runs browser-based OCR
- Thread onProgress through all PDF conversion functions for OCR progress

package.json

@@ -30,6 +30,7 @@
     "react": "19.2.3",
     "react-dom": "19.2.3",
     "smol-toml": "^1.6.0",
+    "tesseract.js": "^7.0.0",
     "woff2-encoder": "^2.0.0",
     "xlsx": "^0.18.5"
   },