libSceMbus technical debt

libSceMbus implements only the no-device path: initialization and termination succeed, no device events are reported and device queries return no entries

libSceMbus (libSceDeviceService) - signatures taken from PPSA01317, which calls sceDeviceServiceInitialize(3, 0), polls sceDeviceServiceGetEventState(1) and queries again when bit 0 or 1 is set, and calls sceDeviceServiceQueryDeviceInfo_(0x7001, 0, 0, infos, 1, &count, &unknown, 0x70), treating a negative result as an error and count as the number of entries. The host has no devices: the event state is 0 and a query returns 0 with count 0
libSceMbus firmware 3.20 pending exports - 115 symbol names are present in the PS5 3.20 libSceMbus export list. Their signatures and console behaviour are unverified. The declarations use the existing no-parameter unknown-signature convention solely to resolve imports, and every call throws through NotImplemented_nid_no_patch.