[BUG] Linux: "import cookies" in the in-app browser wedges the main webview, which is killed and never respawned (permanent black window, app still running)

Environment

• Claude Desktop on Linux (X11 / Cinnamon-Muffin), Electron app installed at /usr/lib/claude-desktop, --ozone-platform=x11
• [CCD] Initialized with version 2.1.280 (from ~/.config/Claude/logs/main.log)

What happened

Opened a GitHub pull request in the in-app browser and chose the import cookies option. The in-app browser wedged, then the whole window became an inert black surface while the app kept running headlessly.

Timeline from ~/.config/Claude/logs/:

• 15:11:30 renderer --renderer-client-id=17 created for the in-app browser; 15:11:35–15:11:40 it loads the github.com PR page (the only two lines ever written to in-app-browser.log are github.githubassets.com preload warnings)
• chose import cookies
• 15:12:08 main.log: Main webview is unresponsive, will kill and reload
• no new renderer process is ever created. Both pre-existing renderers survive that line — client-id 6 (main window, started 15:06:17) and client-id 17 (in-app browser, 15:11:30) — and the main window paints nothing from then on
• claude.ai-web.log stops at 15:06:20 (app start); the web layer emits nothing during or after the freeze
• nothing anywhere in main.log mentions cookies or the import itself

Symptoms

• The main window renders a uniform black surface, no interaction possible. Verified objectively with xwd: the 8 MB capture gzips to 21 KB (i.e. uniform), versus 168 KB for the same window after a healthy restart.
• Everything except the UI keeps working: main process, GPU process, utility processes, MCP servers and the local Claude Code sessions. main.log kept logging PR polling, [process-memory] intervals, and at 15:17:07 even Emitted tool permission request … for AskUserQuestion — a session asking a question that can never be answered, because there is no UI to answer it in.
• Desktop notifications stop arriving; they surface in the browser's claude.ai tab instead.
• Memory at the time: tree_rss_sum≈7150MB, electron(10)=1434MB, children(74)=5718MB — no OOM (sys_free=17.5GB/31.8GB).

Recovery attempts that did not work (app left running throughout)

1. Window resize nudge to force relayout/repaint — still uniform.
2. kill -TERM on the in-app browser renderer (client-id 17) — still uniform.
3. kill -TERM on the main webview renderer (client-id 6) — surface changed from black to blank, and no renderer was respawned. Process inventory dropped to 1 gpu-process, 6 utility, 3 zygote, 0 renderers, and stayed there.
4. Second-instance handoff (/usr/bin/claude-desktop launched again while the first instance held SingletonLock). main.log: second-instance: suppressing duplicate argv, Not main instance, returning early from app ready, then mainView bounds were stale on focus — resyncing (wayland resize race?) — note this session is X11, not Wayland. Still no renderer.

Only a full restart recovered it. On restart: [CCD-SessionRecovery] Scan complete: 54 recoverable and the UI came back normally.

Expected

• Importing cookies should not wedge the in-app browser webview.
• When the app logs Main webview is unresponsive, will kill and reload, the reload should actually produce a new renderer process. Today the app reaches a state with zero renderers and never self-heals, and there is no visible reload affordance on the black window — the only exit is killing the app, which takes every in-flight local session with it, including ones blocked on a permission prompt.

Possibly related

• #87764 — Desktop Browser pane has no way to use existing browser login state
• #95088 — Chrome cookie import fails on macOS (Safe Storage key in the wrong keychain)