~anthropic/claude-sonnet-latest → B (6:4)

Side B introduces a genuinely reusable, composable URL canonicalization engine (url_rules/engine.rs + registry.rs) replacing ad-hoc string manipulation in path_types.rs, fixing structural issues (proper scheme handling, generalizable per-domain rules, YouTube support) with real unit test coverage of edge cases like breadcrumb phantom segments. Side A adds real feature value (Reddit OAuth linking, UUID-based identity) but is more feature-bolt-on with less architectural improvement, and its projection_apply logic for pending in-batch weight reads is a minor but real fix; both are substantive, but B's refactor yields a cleaner, more maintainable foundation for id canonicalization used project-wide.