Player crash in D3D12 shader library (CLibrary::Serialize) — LeiaViewer build

[dfattal]

Split out of #264, which pooled six crash dumps that turned out to be at least three distinct bugs.

Reported by a partner integrator (Amazon Lab126 / LeiaViewer port, internal ticket UNITY-133).

Signature — dump LeiaViewer.35556

Crash in the D3D12 shader library, in CLibrary::Serialize.

This is the only dump in the batch from the built player — every other one is a Unity Editor process (Unity.exe, plus an AssetImportWorker). That alone makes it a separate bug from #264 and #282, both of which are editor-process crashes.

Why it is filed thin, deliberately

Almost nothing is established about this one:

• No stack trace beyond the faulting module and function.
• No Player.log correlated to it yet.
• Unknown whether it needs a DisplayXR session, a particular scene, or a particular shader variant.
• Unknown whether it is reproducible at all — one occurrence.

Filing it rather than folding it back into #264 because pooling dumps by "crashed near DisplayXR" is exactly what made that issue hard to reason about. A thin issue with an honest scope is more useful than a fourth signature buried in a larger one.

Needed to progress

• The Player.log from the same run.
• Unity version, render pipeline, and graphics API of the built player (D3D12 is implied by the faulting module; confirm it was not -force-d3d12).
• Whether it reproduces, and if so whether it needs the DisplayXR loader enabled.
• Whether the player build shipped a stale or partially-written shader cache — CLibrary::Serialize is a serialization path, so a corrupt or truncated library on disk is a candidate that costs nothing to check.

Related: #264 (main-thread stack overflow), #282 (analytics crash) — the other two signatures from the same dump batch.