feat: Checkboxes and Radio Button Mapping for PDFs (GSoC)

[Dotify71]

This PR implements Checkboxes and Radio Button Mapping (Deliverable 1 from my GSoC Proposal).

Advanced PDF Form Mapping (src/filler.py)

• Previously, filler.py indiscriminately assigned the LLM string output to the Value (/V) property of all Widget types. This breaks when a PDF contains checkboxes or radio buttons (Field Type /Btn).
• Implementation: Added conditional logic inside the loop passing through sorted_annots:
  • Detects if an annotation is a Button (/Btn).
  • Checks the generated LLM response for truthy values (yes, true, 1, x).
  • Dynamically extracts the correct internal ON state identifier directly from the PDF Appearance Dictionary (annot.AP.N).
  • Assigns both the Value (/V) and Appearance State (/AS) to accurately check the box on the final PDF layout, while assigning /Off when falsy.

Strict Boolean Typing (per maintainer feedback)

• The fields dict now accepts Python types as values (e.g. {"is awake": bool})
• build_prompt() detects bool fields and explicitly instructs the LLM to return only the literal string 'True' or 'False'.
• add_response_to_json() strictly coerces LLM output to Python bool for boolean fields.
• filler.py uses isinstance(answer, bool) to activate a checkbox/radio button.

(Note: The previous redundant fixes for #135 and #380 were dropped via a merge with upstream/main)

[Dotify71]

Hi @marcvergees @juanalvv! I've resolved the merge conflicts in Makefile and src/main.py. The PR is now up to date with the latest main branch and ready for review/merge. It includes the fixes for #135 and #380, along with the PDF checkbox/radio mapping feature. Thanks!

[marcvergees]

There's something you should need to care about. You've just implemented the fact that if the output of the LLM is something like "yes", "true", etc, and if the fillable field is a radiobutton, then you active it. But how you that the LLM is gonna return something like this? There should be something in the pipeline and the dict that gives all fields regarding booleans. E.g. the fields dict is {"is awake": boolean}, and tell the LLM to give a boolean specifically True or False, that way, we could verify that the field filled would be something like that. Please fix that and we'll be able to test and merge it.

[Dotify71]

Hi @marcvergees! Thanks for the clear feedback. I've addressed your concern in the latest commit (9feeb78).

The fields dict now carries Python type annotations (e.g. {"is awake": bool}). When build_prompt() sees a bool field, it explicitly instructs the LLM: "You MUST respond with ONLY the literal word True or False." The response is then strictly coerced to a Python bool in add_response_to_json() — any unexpected value logs a warning and defaults to None. Finally, filler.py uses isinstance(answer, bool) instead of fuzzy string matching, so only a guaranteed Python True activates a checkbox/radio button. Ready for re-review!

[Dotify71]

Hi @marcvergees! I've updated the PR. I pulled in the latest changes from main to resolve the merge conflicts and dropped my old redundant fixes for #135 and #380 (since you guys already took care of those!).

The PR is now strictly focused on the GSoC Checkbox and Radio Button mapping feature, and it incorporates your feedback regarding strict boolean typing. It's fully up to date and ready for you to take another look whenever you have a moment. Thanks!