Test build for missing areas and floors (#1133)

This build is for players stuck where the next area is not drawn, or where Kratos falls through the floor. It is not a final release: it tells us whether a memory fix removes the problem, and if not, what happens to the game's memory at that spot.

What changes

• Memory fix. When the game swaps one area's memory for another at the same address, a late GPU write for the old area could land on the new one. That write is now dropped and counted in the log. We do not know yet whether this causes the missing floor.
• Texture cache, GPU and shader cache fixes from #1124. On graphics cards with less than 8 GB, texture pressure now starts at 60% of the budget instead of about 40%, and the collector no longer gets stuck behind images it must keep.
• Memory diagnostics. With SPARTAN_MEM_TRACE=1 the log records how the game maps and frees its memory. It is off unless you turn it on.
• Everything else is the current main, including the memory fixes from #1005 and the AMD FSR upscaling and frame generation from #1123.

How to test

1. Copy your save folder first. The game may overwrite the autosave.
2. Extract spartanport-windows.zip into a new folder, so your current install stays as it is.
3. Open PowerShell in the new folder and start the game with the diagnostics on:

   $env:SPARTAN_MEM_TRACE="1"; & ".\SpartanPort.exe"

4. Load the save before the area that goes missing, and go through it with the FPS setting you used when it failed.
5. Note whether the area is drawn, whether the floor holds Kratos, and whether you reach the next checkpoint.
6. Copy user/last_run.log before starting the game again (it is overwritten), and reply on #1133 with it.

On Linux, use the AppImage attached here with the same variable.

Validation

• Built on Windows 11 (MSYS2 CLANG64). The GPU tests and the Rust launcher tests pass. The memory tests, including the new ones for this fix and the trace, pass on Linux (Ubuntu 24.04).
• Built and opened on a clean Windows runner by the release workflow. The Linux AppImage started on Debian 13, Ubuntu 24.04, Arch, Fedora 42 and openSUSE Tumbleweed.
• Not checked: the areas that go missing, because they work on our test install. That is what we need you for.