Implement Pennsylvania CTC Reform (Contributed)

[DTrim99]

Summary

Implement two contributed Pennsylvania Child Tax Credit (CTC) reform proposals for policy analysis.

Proposals

Proposal 1: Vermont-Style PA CTC

• Mirrors Vermont's existing CTC structure
• Uses stepped phaseout: 2% reduction rate ($20 per $1,000 increment) above income threshold
• Key difference from Vermont: Expand the $125,000 phaseout threshold to ALL filing statuses (Vermont only has a single threshold)
• Age limit and credit amount should be configurable via parameters

Proposal 2: Federal CTC Match for Young Children

• 50% match of the federal Child Tax Credit
• Limited to children under age 6 only
• No income phaseout (simple match structure)

Technical Requirements

1. Parameters in policyengine_us/parameters/gov/contrib/states/pa/ctc/

   • Separate folders for each proposal (e.g., vermont_style/ and young_child_match/)
   • Include in_effect parameter for each
   • Use active voice for all parameter descriptions

2. Reform files in policyengine_us/reforms/states/pa/ctc/

   • Create __init__.py files
   • Follow existing patterns (e.g., RI CTC, MT CTC)
   • Register in reforms.py

3. Tests in policyengine_us/tests/policy/contrib/states/pa/ctc/

   • Comprehensive test coverage for both proposals
   • Test edge cases: income thresholds, age limits, filing statuses

Acceptance Criteria

• Both proposals implemented with full parameter sets
• __init__.py files created for proper imports
• reforms.py updated with imports and registration
• YAML tests pass for all scenarios
• make format passes
• All parameter descriptions use active voice