Claude GitHub App reacts with eyes emoji but never posts review (Max plan)

## Description

After installing the Claude GitHub App (github.com/apps/claude) on my repository, `@claude review this` comments on PRs receive an eyes (👀) reaction from `claude[bot]` but no review is ever posted.

## Setup

- **Claude Plan**: Max ($100/month)
- **GitHub App**: Installed yesterday via github.com/apps/claude
- **Permissions**: Read access to actions/metadata + Read/write access to checks, code, discussions, issues, PRs, and workflows
- **Repository access**: All repositories
- **GitHub connector**: Connected in claude.ai/settings/connectors
- **Repo visibility**: Private

## Steps to Reproduce

1. Install Claude GitHub App on your account
2. Create a PR (e.g., `feature` → `dev`)
3. Comment `@claude review this` on the PR
4. `claude[bot]` reacts with 👀 emoji
5. No review comment is ever posted

## What I Tried

- Commented `@claude review this` — got eyes emoji, no review
- Commented `@claude review` — got eyes emoji, no review
- Commented `@claude review this` again after connecting GitHub in claude.ai/settings/connectors — got eyes emoji, no review
- Waited over 24 hours — still no review

## Expected Behavior

Claude should post a code review comment on the PR after acknowledging with the eyes emoji.

## Actual Behavior

Claude only reacts with 👀 and never follows up with a review. No error messages, no failed GitHub Actions runs, no check runs created.

## Related Issues

- #591 — Same symptom (eyes emoji, no action)
- #944 — Claude doesn't generate any output from PR review

Start by reproducing the @claude review this comment flow on a private pull request with the Claude GitHub App installed, then inspect the app's reactions, GitHub Actions, and check runs. Compare the behavior with related issues #591 and #944; done means identifying why the 👀 reaction is posted without a review or actionable error.

Written by the indexing model from the issue text.