Variable JUMBF_TYPESConst

JUMBF (JPEG Universal Metadata Box Format) parser with C2PA support. Mirrors ExifTool's Jpeg2000.pm ProcessJUMB/ProcessJUMD box walking:

• 8-byte box header (size, 4-char type), optional pre-box header bytes
• jumb superboxes contain nested boxes; jumd description boxes carry a 16-byte type UUID, 1-byte flags, then optional label/ID/signature
• cbor boxes hold the C2PA manifest, flattened via parseC2PAManifest