Establish a housing fairness tax credit

This bill creates a new housing fairness income tax credit for Montana residents who pay property taxes on their homes or rent-equivalent amounts on their rentals. It directly affects homeowners and renters with household incomes under $150,000 who have lived in Montana for at least nine months and occupied their residence for at least six months of the tax year. The credit amount is calculated based on household income, with higher credits available for lower-income households, and it cannot be combined with the existing residential property tax credit for the elderly. The legislation also clarifies that taxpayers cannot claim this credit if they receive public rent subsidies or property tax subsidies, and it amends several existing Montana code sections to incorporate these new provisions.