docs: keep the technical debt index and end the NGS2 entry with a newline

The rebase onto main deleted docs/dev/TechnicalDebt.md, which is now the
index that points into docs/dev/debt/. Restore it from main and add the
missing final newline to docs/dev/debt/libSceNgs2.native.md.

docs/dev/TechnicalDebt.md

@@ -0,0 +1,33 @@
+# Project technical debt
+
+Entries about one library or component are in [debt](debt/), one file per library or component, under the same sections as this page. Entries that belong to none stay here.
+
+### Build
+
+- The bundled [SPIRV-Tools build](../../core/shader/recompiler/PatchSpirvTools.cmake) replaces the redundancy-elimination source with a build-directory copy that releases processed traversal maps. Remove this patch when the pinned revision includes [SPIRV-Tools #6962](https://github.com/KhronosGroup/SPIRV-Tools/pull/6962). System-dependency builds need the fix in their installed SPIRV-Tools package.
+- Building on Windows requires a specific version of mingw - MinGW-w64 GCC 15.2.0 (`winlibs-gcc15`, `x86_64-ucrt-posix-seh`)
+- Even compiled prx libraries on Windows require nearby (static linking of these dependencies causes conflicts):
+  - libgcc_s_seh-1.dll
+  - libstdc++-6.dll
+  - libwinpthread-1.dll
+
+### Direct memory
+
+- Windows direct-memory backing reserves a paging-file section and commits each mapped guest page before setting its protection. Committed physical contents remain in the section across unmap/remap and are released when the backing and its remaining views are destroyed; commitment is not recovered merely by unmapping a page. Linux retains its existing backing. Peak gameplay memory and Windows versions other than the tested host remain unverified.
+
+### Silent stubs
+
+Throughout the project, every function at every stage either **does exactly what it's supposed to or throws an exception**. Everywhere... except:
+
+### Unknown function info
+
+- AudioIn and NpSessionSignaling exports added without an implementation have assumed signatures
+- `sceNetCtlGetIfStat` signature and 56-byte layout come from PPSA09030's call site and SharpProspero's `SceNetCtlIfStat`; the device kind is always 0, the byte counters are the host's totals over its up non-loopback hardware interfaces (not "since cleared"), and the not-connected result is assumed to match `sceNetCtlGetState`
+- Font, Http2, Net, Ssl, SystemService and libkernel exports imported by PPSA12544 and added without an implementation have unknown signatures
+- The Share, NpTrophy2, NpEntitlementAccess and WebBrowserDialog exports imported by PPSA12544's Unity plugins and added without an implementation have unknown signatures
+- Acm, GameLiveStreaming, Net, NpEntitlementAccess, NpManager, NpWebApi2, VoiceQoS, WebBrowserDialog and libkernel exports imported by PPSA14632 and added without an implementation are declared without parameters
+
+### Functional
+
+- [Cancellation coverage](ARCHITECTURE.md#thread-cancellation) checks deferred request handling and recovery, not full asynchronous support or console ABI compatibility. Cancellation during file/socket I/O, sleep interruption, cancellation versus exit/detach, condition signal conservation under cancellation, and safe rejection of non-null invalid or reclaimed thread handles remain unverified. No console title or homebrew establishes the cleanup NIDs or buffer layout. Accepted asynchronous mode currently has no diagnostic for its deferred behavior.
+- `--to-intel` guest module trampolines are covered only by a synthetic relinker test; no game title has been verified with them on Linux or Windows.

docs/dev/debt/libSceNgs2.native.md

@@ -24,4 +24,4 @@
 - [sceNgs2PanInit / sceNgs2PanGetVolumeMatrix](../../../core/libs/prx/libSceNgs2.native/src/Pan.cpp) (libSceNgs2.native) - follow the PS4 firmware 11.00 `libSceNgs2.sprx`, read and checked against its output for 2, 4, 5 and 7 speakers into 1, 2, 6 and 8 channels; not yet confirmed on the PS5 library. Speakers are taken in the order L R, L R Ls Rs, L R C Ls Rs or L R C Ls Rs Lb Rb and kept in a fixed circular order, not sorted; without angles the defaults are 90/270, 40/110/250/320, 0/40/110/250/320 and 0/40/110/150/210/250/320 degrees. As in that library, defaults converted to radians keep the wrap-around entry in degrees, so angles past the last speaker pan almost fully to it. Error codes are not known for the PS5, so invalid arguments throw, including a speaker angle equal to the unit angle, on which that library loops forever. Angles so large that adding or subtracting a turn leaves them unchanged throw for the same reason
 - [sceNgs2GeomResetListenerParam, sceNgs2GeomResetSourceParam](../../../core/libs/prx/libSceNgs2.native/src/Geom.cpp) (libSceNgs2.native) - the structures (12, 16, 16, 60, 96, 108, 32 and 308 bytes) come from [KytyPS5](https://github.com/KytyPS5/KytyPS5)'s `ngs2.cpp` and match [shadPS4](https://github.com/shadps4-emu/shadPS4)'s `ngs2_geom.h` field for field, but only KytyPS5 gives the behaviour - shadPS4 logs and returns success without writing the output. The defaults (orient front +Z, orient up +Y, sound speed 343, cone 1/360/1/360, rolloff 0/1000000/1/1, doppler factor, full-band, LFE and maximum level 1, two speakers and matrix format 2) are unverified on a PS5 title; KytyPS5 and iStark/PS5PCEM agree on them. PPSA15552 (Dead Cells) calls `sceNgs2GeomResetSourceParam` after creating its racks. A null output address returns `INVALID_OUT_ADDRESS` as elsewhere in the library rather than throwing as KytyPS5 does. `sceNgs2GeomApply` stays unimplemented
 - [sceNgs2GeomCalcListener](../../../core/libs/prx/libSceNgs2.native/src/Geom.cpp) supports only a listener at the origin with front +Z, up +Y and flags 0. The identity matrix and preserved finite velocity and positive finite sound speed follow [KytyPS5](https://github.com/KytyPS5/KytyPS5/blob/df5b9b92be7dfd463b47756b707d6d356a9f0550/src/libs/ngs2.cpp) and [PS5PCEM](https://github.com/iStark/PS5PCEM/blob/d2534bac6325a2c61c0fa88977e5321074304484/src/hle/ngs2_geom.zig) for that case, not a PS5 measurement. Other orientations (including non-unit vectors), translations and flags throw without changing the output; the matrix convention, handedness flags and console error codes remain unverified. Nonfinite input and nonpositive sound speed also throw. Dead Cells (PPSA15552) reaches this call after the custom sampler rack in #4334, but its arguments have not been captured here. Source attenuation, panning and Doppler in `sceNgs2GeomApply` remain unimplemented
-- [NGS2 custom sampler rack](../../../core/libs/prx/libSceNgs2.native/src/Custom.cpp) (libSceNgs2.native, rack 0x4001) - implements bounded support for the custom sampler rack and its built-in module 0x13 (Custom Voice Filter), unblocking PPSA15552 (Dead Cells) startup. Structure layouts come from [shadPS4's ngs2_custom.h](https://raw.githubusercontent.com/shadps4-emu/shadPS4/main/src/core/libraries/ngs2/ngs2_custom.h) (OrbisNgs2CustomVoiceFilterParam, 40 bytes) and live trace correlation from [prosper's hle_audio.cpp](https://raw.githubusercontent.com/mattias800/prosper/main/prosper/src/hle/audio/hle_audio.cpp) (0x40001300 command and parameters like 10000.0f and 0.707f). Routes parameter updates via the 0x40001300 command family into the Biquad filter engine, supporting only filter type 1; other filter types and unmodeled configurations throw.
+- [NGS2 custom sampler rack](../../../core/libs/prx/libSceNgs2.native/src/Custom.cpp) (libSceNgs2.native, rack 0x4001) - implements bounded support for the custom sampler rack and its built-in module 0x13 (Custom Voice Filter), unblocking PPSA15552 (Dead Cells) startup. Structure layouts come from [shadPS4's ngs2_custom.h](https://raw.githubusercontent.com/shadps4-emu/shadPS4/main/src/core/libraries/ngs2/ngs2_custom.h) (OrbisNgs2CustomVoiceFilterParam, 40 bytes) and live trace correlation from [prosper's hle_audio.cpp](https://raw.githubusercontent.com/mattias800/prosper/main/prosper/src/hle/audio/hle_audio.cpp) (0x40001300 command and parameters like 10000.0f and 0.707f). Routes parameter updates via the 0x40001300 command family into the Biquad filter engine, supporting only filter type 1; other filter types and unmodeled configurations throw.