fix(pdf-manager): detect PDFRadioGroup fields instead of classifying as text

[nnhhoang]

Summary

The PDF Manager at /pdf-manager was classifying PDFRadioGroup fields as text. The detection in extractFieldsFromBytes only special-cased PDFCheckBox and treated everything else as text, so radio groups got the wrong type and were shown with the text icon (noticed in #656, the first uploaded form that contains radio groups).

Changes

• pdf-manager/lib/pdf.ts – add a small fieldType() helper that maps PDFCheckBox → checkbox, PDFRadioGroup → radio, and everything else → text, and add "radio" to PdfFieldInfo["type"].
• pdf-manager/src/types.ts – add "radio" to Field["type"].
• pdf-manager/src/components/FieldList.tsx – render a radio icon for radio fields.

The schema generation in lib/schema.ts already records the raw constructor.name, so generated schemas keep flagging these fields as PDFRadioGroup.

Testing

Built an in-memory PDF with a text field, a checkbox and a radio group, then ran extractFieldsFromBytes on it.

Before:

full_name    -> text
agree_terms  -> checkbox
sex_marker   -> text       (radio group — wrong)

After:

full_name    -> text
agree_terms  -> checkbox
sex_marker   -> radio

tsc --noEmit and biome check both pass.

Closes #659

[kydecker]

Tested and everything works! Thank you for your contribution!