chore: gh-aw native OAuth token auth support

[JacobPEvans]

Summary

The gh-aw compiler hardcodes anthropic_api_key: secrets.ANTHROPIC_API_KEY in compiled .lock.yml files. We work around this by setting ANTHROPIC_API_KEY to our OAuth token value.

Ideally, gh-aw should support claude_code_oauth_token as a native auth parameter so we can use CLAUDE_CODE_OAUTH_TOKEN directly without the alias.

Current Workaround

• ANTHROPIC_API_KEY secret contains the OAuth token value
• claude-code-base-action auto-detects token format and handles it correctly

Desired State

• gh-aw supports claude_code_oauth_token in frontmatter
• Compiled .lock.yml uses claude_code_oauth_token: secrets.CLAUDE_CODE_OAUTH_TOKEN
• No need for ANTHROPIC_API_KEY alias

Phase

Backlog - depends on gh-aw upstream support

[JacobPEvans]

Status Update

Workaround implemented in PR #9: the compiled next-steps.lock.yml is manually patched to use secrets.CLAUDE_CODE_OAUTH_TOKEN instead of the compiler's default secrets.ANTHROPIC_API_KEY.

This issue tracks making the gh-aw compiler natively support configurable secret names, eliminating the need for post-compile patching.