Add a setting to disable background agents' auto-commit / auto-push / auto-PR (v2.1.198)

Feature request

v2.1.198 (July 1, 2026) introduced auto PR creation for background agents: per the release notes, a background agent that finishes code work in a worktree now auto-commits, auto-pushes, and auto-opens a draft PR — as a default behavior.

Problem: some of us run propose-only workflows, where agents produce changes but a human reviews, commits, and opens every PR. With this behavior on by default, a background agent finishing its work can push branches and open draft PRs on origin without the human in the loop. I could not find a settings key, /config option, or any documented way to turn it off (checked the settings docs and the v2.1.198 changelog/release notes).

Ask (either would work):

1. A configuration key to disable the behavior — e.g. backgroundAgents.autoCreatePr: false, ideally with separate knobs for auto-commit / auto-push / auto-PR — settable in settings.json and via /config; or
2. Have background agents respect existing permission deny rules (e.g. Bash(git push:*)) so the behavior can be blocked with the current permission system.

Why it matters: pushing branches and opening PRs is outward-facing. For workflows where the human is the only one allowed to publish, a default-on publish step needs an off switch.

Environment: Claude Code v2.1.198, macOS (darwin).