Phase A.1 reverted to synchronous mode due to DatCollection thread-
safety; T10 documented the lock that makes concurrent reads safe. T11
activates the dedicated worker thread and switches enqueue methods
to non-blocking Channel.Writer.TryWrite.
EnqueueLoad now takes LandblockStreamJobKind (default: LoadNear from
all callers, matching previous full-load semantics). T13/T16 will
route by kind per TwoTierDiff.
Constructor gains optional buildMeshOrNull param (defaults to null-
returning stub); T12 wires the real LandblockMesh.Build factory.
GameWindow construction site updated: Action<uint> enqueueLoad
delegate now wraps a lambda (method group won't bind to Action<uint>
when the method has an optional second param).
LandblockStreamerTests updated: the synchronous-thread-pinning test
replaced by Load_ExecutesLoaderOnWorkerThread which asserts the
loader runs on a different thread; Load_FollowedByDrain now supplies
a stubMesh so the worker can produce Loaded (not Failed) results.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>