Add setting to disable/hide the PR diff viewer by default in Claude Desktop app

Feature request

When using Claude Code inside the Claude Desktop app, a PR/git diff pane is shown. For my workflow this diff view isn't useful and I'd like it off.

Currently the only options are session-level visibility toggles (Cmd/Ctrl+Shift+D to hide the pane, Cmd/Ctrl+\ to close the focused pane) — but these don't persist, so the diff pane reappears in new sessions.

Request: a persistent setting (in Desktop app settings or settings.json) to disable/hide the PR diff viewer by default.