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

Side B fixes a real production bug (empty /-/ external garden index due to bogus parent), refactors external_resolver into a resolvers/ module with typed GithubImportCard rendering, wires it through vote-compare and item pages, and adds integration/unit tests plus CSS. Side A adds a new URL-canonicalization graph engine with extensive tests but is a standalone/net-new feature not shown to fix any existing defect or integrate with the rest of the app in this diff, making B's change more clearly load-bearing and battle-tested.