[BUG] Desktop 1.24012.9 (Windows MSIX): GPU/viz process crashes on WebGL/Cloudflare pages, then MSIX activation blocked (0x80073CFC) until reinstall

Environment: Windows 11 Pro 26100, Claude Desktop 1.24012.9 (MSIX), CCD 2.1.215 and 2.1.219, AMD RX 7900 XTX (latest Adrenalin + chipset drivers). Previous version 1.22209.3 was fine.

Repro: Open a WebGL-heavy / Cloudflare-protected page (e.g. battlemetrics.com) in the built-in browser pane. The GPU process crashes and takes the whole app down. Reproduced 5+ times today. Pages without WebGL (example.com, wikipedia.org) are stable.

Logs (%APPDATA%\Claude\logs\main.log):

GPU process gone: { type: 'GPU', reason: 'crashed', exitCode: 101457950, serviceName: 'GPU' }

preceded by [CDPTools]/[Preview] screenshot failures with UnknownVizError, and unknown-window.log shows repeated WebGL: INVALID_ENUM: getInternalformatParameter warnings in the same second.

Ruled out on my machine:

• GPU driver + chipset updated, shader caches (GPUCache/Dawn*) cleared -> no change
• Launched with --disable-gpu: GPU process still crashes with the SAME exit code 101457950 (0x060C201E) -> hardware/driver independent, crash is in the viz path
• No custom Exploit Protection (Get-ProcessMitigation: all NOTSET), Windows Defender only

No crash dumps ever: at each crash second, the Microsoft-Windows-Security-Mitigations/KernelMode event log records Event 36: WerFault.exe blocked from calling NtFsControlFile - the sandbox FSCTL filter appears to prevent dump writing. The Crashpad reports directory stays empty.

Secondary bug - app cannot restart after the crash: AppModel-Runtime/Admin logs

0x80073CFC: process for package Claude_1.24012.9.0_x64__pzs8sxrjxfjjc cannot be created [GetPackageToken]

The package status is stuck at 0x2 until an install-over resets it to 0x0. Repair does not fix it, and there are no lingering claude.exe processes (taskkill /f /im claude.exe finds nothing). So every crash currently forces a full reinstall.