Desktop Browser pane: Cloudflare challenge page crashes GPU process, app restarts (exit 101457950)

Summary

Opening the Claude Code desktop Browser pane on a site behind a Cloudflare managed challenge ("Just a moment...") crashes the Electron GPU process and the whole desktop app restarts, losing the session. Reproduced twice in a row, same signature.

Environment

• Claude desktop app 1.40609.1 (MSIX install, auto-update disabled), embedded Claude Code 2.1.255
• Windows 11 Pro 10.0.26200, x64, 64 GB RAM (sys_free ~36 GB at crash time)

Repro

1. In a desktop session, call the Browser pane (preview_start / navigate) with https://seed.tacobuild.com/... (any URL on that host serves a Cloudflare managed challenge).
2. Page shows "Just a moment... Performing security verification".
3. ~1 s later the GPU process crashes; the app restarts ~90 s later.

Log (main.log, both occurrences identical)

2026-09-03 23:56:25 [warn] [PreviewContext] Blocked subresource to private-resolving host { resourceType: 'xhr' }
2026-09-03 23:56:25 [info] GPU process gone: { type: 'GPU', reason: 'crashed', exitCode: 101457950, serviceName: 'GPU' }
2026-09-03 23:57:51 [info] Starting app { appVersion: '1.40609.1', ... }
...
2026-09-03 23:58:51 [warn] [PreviewContext] Blocked subresource to private-resolving host { resourceType: 'xhr' }
2026-09-03 23:58:51 [info] GPU process gone: { type: 'GPU', reason: 'crashed', exitCode: 101457950, serviceName: 'GPU' }
2026-09-03 23:59:26 [info] Starting app { appVersion: '1.40609.1', ... }

No Windows Application Error / WER event was written, so this is the Electron GPU child dying and the app relaunching itself, not an OS-level crash.

Expected

GPU process loss should not take the whole app and the active Claude Code session down; the pane tab should fail in isolation (or the app should survive a GPU restart).

Notes

• The challenge page's fingerprinting (WebGL / workers) is the likely trigger; the [PreviewContext] private-host XHR block fires immediately before each crash.
• /bug is not available from claude -p, so filing here.