~anthropic/claude-sonnet-latest → B (80:20)

Side B is a substantial, structural refactor introducing a generalized ItemId/tree model (path_types, reducer's GlobalTree/NodeState, journal.rs replacing settlement.rs, breadcrumb rendering, reddit.rs) that changes the core data model to support hierarchical ranking beyond just subreddits, backed by new unit/integration tests. Side A is a narrower, useful but low-risk test-infrastructure fix (correcting regex usage, HttpExchange methods, exception handling in mock OAuth server) that restores E2E test reliability but adds no new product capability.