Dev + Review Loop Subagent Example within Gemini CLI Repo

Update the existing review skill to utilize custom subagents + parallel invocation to create a review loop that the main agent (orchestrator) can call.

The goal here is to have the main agent's work be reviewed by specialized personas that work in parallel to provide high quality feedback and double check work.

Example iteration:

1. Bug Provided to main agent
2. Main agent plans and implements changes
3. Once the main agent is happy with its changes, it activates a self-review cycle via skill
4. Parallel subagents work to review the complete change and original bug to ensure completeness, correctness, and ensure no regressions.
5. Feedback from subagents is fed back to the main agent to either make corrections or proceed.