feat(libs): add exports imported by PPSA12544

Implement scePthreadGetschedparam and scePthreadSetschedparam on top of
the thread priority, POSIX utimes and fsync on top of sceKernelUtimes
and sceKernelFsync, and sceUserServiceGetAccessibilityZoomFollowFocus
like the other accessibility queries. Add the remaining imports of
PPSA12544 as unimplemented exports and record unknown NIDs and
signatures in the technical debt.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

docs/dev/TechnicalDebt.md

@@ -60,6 +60,11 @@ Throughout the project, every function at every stage either **does exactly what
 - [BnMAMrsfVWo](../../core/libs/prx/libc/src/HeapDiagnostics.cpp) (libc) - unknown name, signature
 - [scePngEncEncode](../../core/libs/prx/libScePngEnc/Export.cpp) (libScePngEnc) - whether rows may stay unfiltered when `filter_type` names a subset of the filters is unknown; as in shadPS4, they may only for 0 and for the all-filters mask
 - AudioIn, NpSessionSignaling and PlayerInvitationDialog exports added without an implementation have assumed signatures
+- [dbOlWdppb4o, vieBRwlh1Lw](../../core/libs/prx/libSceAgc/Unimplemented.cpp) (libSceAgc) - unknown name, signature
+- [OQ-dzhlnM28, qBS714-Jr3g, tB59hFLH3SA](../../core/libs/prx/libc/src/HeapDiagnostics.cpp) (libSceLibcInternalExt, implemented in libc) - unknown name, signature
+- [fCWdlnmB1Ks](../../core/libs/prx/libScePad/Export.cpp) (libScePad) - unknown name, signature
+- [B2n8aDorSH4, NH6xARDOVv8, PZQhiiLXRFs](../../core/libs/prx/libkernel/Unimplemented.cpp) (libkernel) - unknown name, signature
+- Font, Http2, Net, Ssl, SystemService and libkernel exports imported by PPSA12544 and added without an implementation have unknown signatures
 - [libSceAudioPropagation](../../core/libs/prx/libSceAudioPropagation/Export.cpp) (libSceAudioPropagation) - signatures and struct descriptors recovered from PPSA21567's calls (#481), not from documentation. The system options layout is unknown (only checked for non-null); the fourth argument of `sceAudioPropagationSourceCalculateAudioPaths` is unknown; `sceAudioPropagationSourceGetAudioPath` is assumed to output an 8-byte path handle. The meaning of the `RenderInfo` word at +0x28 is unknown (PPSA21567 and PPSA21564 pass 2); only 2 is accepted. Both titles pass one `RenderInfo` per call: a count of 0 throws, and larger counts are handled element by element without proof. No error code is known, so invalid input throws instead of returning one
 - [sceAvPlayerStartEx](../../core/libs/prx/libSceAvPlayer/Export.cpp) (libSceAvPlayer) - start info layout unknown; it is ignored and playback starts as with `sceAvPlayerStart`
 - [sceAvPlayerInit / sceAvPlayerInitEx](../../core/libs/prx/libSceAvPlayer/src/Player.cpp) (libSceAvPlayer) - behaviour without a memory replacement unknown; frame and sample buffers then come from the guest heap