ap streams to show the new modified values

[mohamed-mostafa-18]

Summary

• Generate explicit /AP (appearance stream) for each filled text and choice field so all PDF renderers display values — not just full viewers like Mac Preview
• Fill both AcroForm field objects and page annotation widgets, since some PDFs store these as separate objects with the same field names
• Add inline Type1 font fallback for templates missing AcroForm default font resources (/DR)
• Remove NeedAppearances flag after filling since we now provide proper appearance streams
• Skip /AP generation for button fields (checkboxes/radio buttons) which already have pre-built appearances

Context

Filled PDFs showed values in Mac Preview but appeared empty in Slack, Chrome, Google Drive, and Adobe Web. The binary was setting /V values and relying on NeedAppearances = true to tell viewers to render them, but lightweight renderers ignore that flag.

Test plan

• All existing unit and integration tests pass
• New unit tests for appearance stream generation, font parsing, PDF escaping, and NeedAppearances removal
• New integration test verifying /AP streams exist on filled fields
• Verified filled NM template shows values in Mac Preview