workflow validation failed if base branch's name has # in it

**Describe the bug**
If change base branch into something like `feat/#689-v1.2.0`, then Claude Code actions failed with `workflow validation failed` error. If we rename base brach(of course, no changes in workflows) like `develop/v1.2.0`, then workflows works fine.

**To Reproduce**
Steps to reproduce the behavior:

1. Go to your repository (where Claude Code actions workflow already exists) in Github
2. Go to `Settings`
3. In `General`, find `Default branch` menu
4. change Default branch into something has `#` in it

**Expected behavior**
A clear and concise description of what you expected to happen.

Then Claude Code actions start to fail with below message
```
Warning: Skipping action due to workflow validation: Workflow validation failed. The workflow file must exist and have identical content to the version on the repository's default branch. If you're seeing this on a PR when you first add a code review workflow file to your repository, this is normal and you should ignore this error.
```

**Screenshots**
If applicable, add screenshots to help explain your problem.

**Workflow yml file**
If it's not sensitive, consider including a paste of your full Claude workflow.yml file.

**API Provider**

[ ] Anthropic First-Party API (default)
[ ] AWS Bedrock
[ ] GCP Vertex
I used Github apps for claude connection

**Additional context**
Add any other context about the problem here.

No source file or test is named. Reproduce the failure by setting the repository default branch to a name containing `#`, such as `feat/#689-v1.2.0`, then compare it with `develop/v1.2.0`; done means Claude Code actions validate and start successfully without the reported workflow validation error.

Written by the indexing model from the issue text.