~anthropic/claude-sonnet-latest → B (75:25)

Side B is a concrete, tested bugfix/feature: it enforces sane vote-ratio bounds across DSL parsing, HTTP handler, and reducer, with matching unit/integration test updates and a corrected browser test fixture. Side A is only a planning document plus a thin, largely unused RouteContext wrapper that duplicates existing ThreadNav methods without migrating any call sites, providing no functional change or bugfix.