fix: unblock reviewer swarm permissions

[cgaravitoq]

Summary

Fix reviewer swarm failures caused by missing review-state directories and overly narrow bash allowlists.

Changes

• Create the review-state directory before the guardrail plugin writes swarm budget state.
• Expand reviewer bash permissions for git/repo inspection and read-only shell commands.
• Keep subreviewers read-only by preserving write/edit/patch/task restrictions.
• Add a regression test for first reviewer task budget write in an empty state directory.

Verify

• bun test - pass
• git diff --check - pass