feat(stamphog): trust clean ReviewHog signals

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Problem

This repo’s older Stamphog copy did not fetch PR reactions, so it could not consume clean reviewer signals from Greptile, Hex, or ReviewHog.

Why: Keep Stamphog’s reviewer evidence consistent across PostHog repos through one generic trusted-reaction contract.

Changes

• Fetch PR reactions and retain only allowlisted reviewer bots, excluding the PR author.
• Include the normalized reactions in the reviewer prompt with generic weak-evidence semantics.
• Trust the shared posthog[bot] identity used by ReviewHog alongside the existing reviewer bots.

How did you test this?

• uv run --with pytest python -m pytest tools/pr-approval-agent/test_github.py tools/pr-approval-agent/test_review_pr.py tools/pr-approval-agent/test_reviewer_gateway.py
• 16 focused tests passed.
• ruff check passed on the changed Python files.

Automatic notifications

• Publish to changelog?
• Alert Sales and Marketing teams?

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Created with PostHog Code

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