Silverdar passthrough and local I/O integration

Local gateway I/O addressing and dedicated core-board device documentation were specified. Documentation changes were reported, without a final commit result or proof of device integration/control.

Review found that incomplete binary frames could reach newline-based text handling too early. laan requested a full review and isolation from the established path. Evening reports said fragmented/multiple-frame handling was repaired locally, with focused unit/TCP integration and old-path checks passing. The repair was uncommitted and production still ran the earlier version. Neither deployment of the fix nor independent real Silverdar acceptance was established.