Electoral redistricting in single-member plurality systems requires drawing boundaries that satisfy competing legal, geographic, and demographic constraints -- yet the tools available to those who draw the lines remain opaque, fragmented, or inaccessible to the publics they affect. We present the MaRiPoSa Redistribution Modernization Platform (MRMP), an open-source, full-stack web application designed to support the redistribution of Canada's 343 federal electoral districts. Built on Statistics Canada census boundary data across all thirteen provinces and territories, the platform integrates interactive map editing, real-time electoral analytics, and computational redistricting methods within a unified interface accessible to commissioners, researchers, and the public alike. An AI-assisted advisory system with 61 domain-specific tools translates between computational outputs and redistricting criteria, while community overlays, compactness metrics, partisan fairness measures, and census demographic profiles enable users to evaluate plans against the substantive standards that redistricting commissions are legally required to balance. MRMP does not automate redistricting decisions; it renders visible the trade-offs among population parity, community preservation, and geographic compactness that boundary commissions navigate—trade-offs otherwise buried in the combinatorial complexity of the mapping problem itself. By bridging computational methods and democratic accountability within a single platform, this contribution provides infrastructure for both applied redistricting practice and empirical research on boundary effects in Canadian elections.