libSceSisrSys technical debt

sceSisrSysProcessUmdEvent and sceSisrSysSetup - names and NIDs are present in the complete PS5 13.60 export inventory, and the pinned module map assigns both identities to the physical libSceSisrSys.sprx provider. Parameter lists, return types and behavior are unverified; the parameterless int declarations are import-resolution placeholders, not verified ABI contracts. Both entries throw through NotImplemented_nid_no_patch. No SISR setup or UMD-event behavior is implemented.