[Bug] step0_fork_prs ignores GITHUB_TOKEN in .env file

[Yuto-24]

Describe the bug

The script step0_fork_prs fails to recognize the GITHUB_TOKEN defined in the .env file, even though the documentation suggests it should. It only works when the token is provided explicitly via the --token argument.

Steps to Reproduce

1. Copy .env.example to .env.
2. Set GITHUB_TOKEN in the .env file:

   GITHUB_TOKEN=ghp_MY_SECRET_TOKEN

3. Run the following command:

   uv run python -m code_review_benchmark.step0_fork_prs \
     --org test--yuto-personal \
     --name Gemini

Actual Behavior

The command fails with the following error:
Error: Set GITHUB_TOKEN or use --token

Expected Behavior

The script should load the token from the .env file automatically, as implied by the offline/README.md.

Workaround

Giving the token inline works correctly:

uv run python -m code_review_benchmark.step0_fork_prs \
  --org test--yuto-personal \
  --name Gemini \
  --token ghp_MY_SECRET_TOKEN

Environment

• Repository: withmartian/code-review-benchmark
• Script: code_review_benchmark.step0_fork_prs