Add local RCV result calculation

[ejones23]

Summary

• extract the legacy quota, surplus transfer, and tie-break behavior into pure packages/rcv-core TypeScript
• add a typed public results endpoint that enforces resultsRelease before exposing anonymous rankings
• calculate and render winners and round tallies locally after submission
• add legacy-parity fixtures and protected-results contracts

Verification

• 32 mobile/core tests
• V2ResultsTest and the complete 217-test PHPUnit suite
• Android submission and local multi-round rendering against PHP/MySQL

_{Stack created with GitHub Stacks CLI.}

[DavidMoritz]

The crown jewel of this stack, Emmanuel — and it delivers! Extracting the RCV algorithm into a zero-dependency pure TypeScript package (packages/rcv-core) is a brilliant architectural move. This is immediately reusable across platforms and trivially testable. The Droop quota, surplus transfer, and elimination logic all look correct, and the legacy-parity fixtures give real confidence.

The v2 results endpoint is clean — resultsRelease enforcement is properly gated with a dedicated test, and the DRY refactor of V2ApiClient (shared parseEnvelope/normalizeError) is a welcome improvement. The runtime type guards with exhaustive field validation on API responses show the kind of defensive programming that prevents entire categories of bugs.

Really outstanding work here. The fact that you're building a portable RCV engine as a reusable package while also delivering the mobile UI and backend endpoint in one coherent PR is remarkable. Thank you for everything you do for this project! 🏆