Add the SE2 release archive

[viktor-ferenczi]

Shared patched DXVK, SE2-only vkd3d-proton and FMOD, bare-named library layout. Split to three archives.

Details

Restructures the releases into three assets and adds Space Engineers 2 support, importing the native libraries and patches from the SE2 port workspace (dotnet-game2-local):

• se1-dependencies.tar.gz (renamed from linux-dependencies.tar.gz) — the SE1 payload, with the DXVK binaries now being the patched build (byte-identical to the SE2 archive's copies).
• se2-dependencies.tar.gz (new) — everything the SE2 Linux port needs.
• steam-dependencies.tar.gz (new) — Steamworks.NET.dll + libsteam_api.so, the managed binding and its native runtime belong together. Pulsar depends only on this binary archive for its own Linux support.

Every library file is under its bare (unversioned) name (see the layout section below) and there are no versioned symlinks provided.

Every library is built once.

Archive contents

Artefact	se1	se2	steam	Origin
FFmpeg, OpenAL, EOS	yes	—	—	unchanged
DXVK 2.7.1 + Patches/dxvk/	yes	yes (same bytes)	—	built once
vkd3d-proton @ 3dfc6f07d095 + Patches/vkd3d-proton/	—	yes	—	new, SE2-only (SE1 never shipped a D3D12 layer)
FMOD Engine 2.03.11 (libfmod.so, libfmodstudio.so)	—	yes	—	Vendor/ blob (SE1 does not use FMOD)
Steamworks.NET.dll + libsteam_api.so	—	—	yes	moved out of the SE1 payload

The SE2 native wrappers (libVRage.*.Native.so) are not shipped here — like the SE1 PE-loader shims, they are built and released by linux-native-wrappers and fetched separately.

Archive layout: bare names only

Both archives now contain only real files under bare, unversioned names — no symlinks, no .so.62/.so.14-style suffixes. To keep the bundles self-resolving under DT_RUNPATH=$ORIGIN, the built libraries' intra-bundle NEEDED entries are rewritten to the bare names with patchelf --replace-needed at staging (FFmpeg chain, libdxvk_d3d11 → libdxvk_dxgi); SONAMEs inside the binaries stay upstream, and the SOVERSION/SONAME assertions remain as ABI-bump tripwires. The FMOD blobs stay byte-unmodified, so libfmodstudio.so still references libfmod by SONAME internally — consumers must load libfmod.so before libfmodstudio.so (documented in consuming.md). Verified: zero symlinks/suffixed names in both archives, every staged library dlopens with sibling resolution from its own directory, FMOD preload order works.

The patches

• DXVK — 0001-dxgi-windows-abi-16-bit-wchar.patch: DXVK Native defines WCHAR as Linux's 32-bit wchar_t, so IDXGIAdapter::GetDesc* writes 560 bytes into the caller's 304-byte Windows-ABI buffer (Vortice/SharpDX marshal 16-bit WCHAR), corrupting managed memory. The patch makes WCHAR 16-bit, transcodes the SDL display name at the WSI boundary, and adds compile-time asserts for the Windows x64 struct sizes. The SE2 port's original DXVK checkout (commit d592777f) was not preserved, so this is a reimplementation from its Finding 012 — verified with a raw-COM-vtable GetDesc test using guard words (exactly 304 bytes written, UTF-16 description) against the real adapter.
• vkd3d-proton — imported verbatim from the SE2 repo: the DXGI adapter-parent fix (prevents a null dereference in CreateSwapChainForHwnd under native DXGI) and an SE2_CPU_RENDERING-gated llvmpipe FP64 override (inert unless the env var is set). Pinned to the upstream commit the series was tested against.

Build changes

• build_dxvk.sh: single build, patch series always applied; series SHA-256 is part of the cache stamp; pristine reset before each apply. The patched files are copied into the SE2 staging tree (same bytes in both archives).
• New Scripts/build_vkd3d_proton.sh: fetch-by-SHA (depth 1) + submodules, same patch/stamp mechanics, DT_RUNPATH=$ORIGIN, staged straight into Libraries-SE2/. Requires widl — CI installs mingw-w64-tools, the script shims x86_64-w64-mingw32-widl onto PATH, and local builders need that package too (documented in building.md).
• FMOD blobs committed under Vendor/ next to EOS/steam_api, staged SE2-only.
• Licenses: SE1 LICENSES/ unchanged; the SE2 archive adds FMOD EULA + notice and VKD3D LGPL-2.1 + a provenance/relinking notice (same LGPL obligation pattern as FFmpeg), sourced from Licenses/se2/.

Verified locally

• Full ./build.sh: both archives packaged; the SE1 archive's file list matches the pre-split contract exactly; SE1/SE2 DXVK files are cmp-identical; DXGI ABI smoke test passes against the staged patched libdxvk_dxgi.so.
• Patch mechanics: cache hit, series-hash invalidation, pristine reset, and clean failure on a non-applying patch all exercised.

Notes / follow-ups (not in this PR)

• The DXC stack (DxcCompilerBridge + pinned libdxcompiler/libdxil from the port's RenderingLibs/) was deliberately left out — it is a cohesive follow-up needing DXC SDK headers.
• linux-native-wrappers needs to publish the SE2 wrapper set (libVRage.*.Native.so) for SE2 consumers to fetch.
• Breaking for consumers: (1) the asset renames — fetch scripts must download se1-dependencies.tar.gz and additionally steam-dependencies.tar.gz for the Steam bits, which are no longer inside the SE1 archive; (2) the bare-name layout — loaders referencing versioned names (libavcodec.so.62, libopenal.so.1, libdxvk_*.so.0) must switch to the bare names. Expected-file lists need updating; the consumers' existing stale-file cleanup handles the removed symlinks/versioned files.