D6: Add ExportSubjects/ImportSubjects allow-lists to LeafHubSpokeMapper alongside
existing DenyExports/DenyImports deny-lists. When an allow-list is non-empty, subjects
must match at least one allow pattern; deny always takes precedence. Updated
LeafNodeOptions, LeafHubSpokeMapper (5-arg constructor), and LeafNodeManager to wire
through the new allow-lists. Added 13 new unit + integration tests covering allow-list
semantics, deny precedence, bidirectional filtering, and wire-level propagation.
D7: Existing NetworkingGoParityTests.cs (50 tests) covers gateway interest mode,
route pool accounting, and leaf node connections. Parity DB already up to date.
Joseph Doherty
37d3cc29ea