fix(review-pr): remove unsupported before_llm_call hooks from drafter and verifier agents

[docker-agent]

Problem

The hooks.before_llm_call hook type does not exist in any released version of docker-agent (latest: v1.57.0). Both the drafter and verifier sub-agents in review-pr/agents/pr-review.yaml had these blocks:

hooks:
  before_llm_call:
    - type: builtin
      command: max_iterations
      args: ["40"]

This caused both agents to crash immediately at startup with an "unknown field" error, breaking the entire PR review pipeline.

Fix

Remove both hooks.before_llm_call blocks entirely (one from drafter, one from verifier).

Validation

• pnpm build ✅
• pnpm lint (biome + tsc + actionlint) ✅

[docker-agent]

Assessment: 🟢 APPROVE

The change correctly removes two hooks.before_llm_call blocks (one each from drafter and verifier) that referenced an unsupported hook type in docker-agent v1.57.0. Since the hook type does not exist, these blocks were already non-functional and caused startup crashes. The removal is symmetric across both agents, no new logic is introduced, and pnpm lint (biome + tsc + actionlint) passed cleanly.

No bugs were found in the added code. The only consideration raised — that max_iterations: 40 is no longer enforced — is an inherent consequence of removing broken configuration, not a defect introduced by this PR.