Revise the definition of public school system and requirements of school funding formula

SB 215 revises Montana's public school funding system by redefining the "basic system of free quality public schools" to explicitly include open enrollment, student achievement tracking, and transparency in spending. It requires the legislature to consider specific factors when setting funding - such as student needs (including special education, English learners, and American Indian students), school density, and teacher retention - while mandating that funding follows students across district lines during open enrollment. The bill also directs the funding formula to use current-year enrollment data, include annual cost-of-living adjustments, and clearly show how funds impact student outcomes. These changes apply to all public school districts in Montana, aiming to make funding more equitable and accountable.