libSceSaveDataDialog.native technical debt

libSceSaveDataDialog.native shows no UI and ignores progress values. Progress-bar mode (5) stays running until the caller closes it, matching Skyrim PPSA03747; other modes finish immediately, returning button 1 and the first nonempty directory name. Console dialog timing and selection behavior remain unverified. Lifecycle error codes follow shadPS4: sceSaveDataDialogClose returns SAVE_DATA_DIALOG_ERROR_NOT_RUNNING whenever not running, sceSaveDataDialogGetResult returns SAVE_DATA_DIALOG_ERROR_NOT_FINISHED whenever not finished (checked before null or unwritable result and directory pointers), and sceSaveDataDialogTerminate closes running dialogs and returns OK, rejecting uninitialized calls with SAVE_DATA_DIALOG_ERROR_NOT_INITIALIZED, and progress updates (sceSaveDataDialogProgressBarInc, sceSaveDataDialogProgressBarSetValue) return SAVE_DATA_DIALOG_ERROR_NOT_RUNNING whenever not running. Parameter size in sceSaveDataDialogOpen is unvalidated as console behaviour is unmeasured.
sceSaveDataDialogIsReadyToDisplay returns 1 unconditionally without checking state, following shadPS4 (savedatadialog.cpp at ce74386283); native console readiness state is unmeasured.

sceSaveDataDialogGetResult (libSceSaveDataDialog.native) - returning SAVE_DATA_DIALOG_ERROR_ARG_NULL for a non-null unwritable result or directory name pointer is a host-safety fallback; console behaviour for unmapped memory is unmeasured. Closes when: measured on a PS5
sceSaveDataDialogOpen (libSceSaveDataDialog.native) - no overlay dialog is drawn for any mode: the layouts of the user message, system message and error code parameters that the SaveDataDialogParam pointers lead to have no source in this repository or measurement on a PS5, so a dialog is not built from them. Closes when: the parameter layouts are measured on a PS5