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

Side B introduces a genuinely new, composable URL-canonicalization subsystem (url_rules module with engine + registry, domain-specific rules for reddit/youtube, breadcrumb/parent derivation) that fixes real correctness issues (schemeless IDs, non-canonical hosts, youtube variants) and is exercised by substantial new tests. Side A is a solid internal refactor (GroupState -> ScopeVotes, deriving edges on demand) that improves clarity but is mostly mechanical renaming/restructuring of existing logic without adding new capability or fixing an external-facing bug, making B's contribution somewhat more impactful in scope though both are reasonable quality refactors.