The scheduler's runtime HiCache attach/detach wrote its own ServerArgs so the
internal-state readback would show the change; that readback already reports
the resolved config, so the writes become get_context().override(...) and the
namespace readers see them too.
The tokenizer side is per-engine — several Engines can share one process — so
its control-plane updates (weight version, model path + load format, HiCache
attach/detach) stay with the manager instead of moving to the process-global
bags. TokenizerManager gains record_config_updates / config_value /
resolved_config_dict, and the readbacks that used to observe the instance write
(/server_info, /model_info, the HiCache status endpoint, the gRPC bridge) now
overlay those updates onto the startup config.
test_server_info's stub grew the real manager instead of a SimpleNamespace, so
the overlay it now exercises cannot drift from production.
Writer ratchet 26 -> 19.
Cheng Wan
0b3e8bedd1