fix: handle invalid users in data workflows

[AleksZyro]

Description

Fixes #542

Changes Made

• Stage invalid-users.json together with inactive-users.json in the inactivity-analysis workflow.
• Explicitly exclude invalid-users.json from the sync workflow staged changes, matching the existing handling for generated data files.

Type of Change

• Bug fix

Testing

• Tested locally
• No console errors introduced (workflow-only change)

Validation performed:

• npx prettier@3.8.3 --check .github/workflows/analyze-inactivity.yml .github/workflows/sync-leaderboard.yml passed.
• Both changed workflow files parsed successfully as YAML.
• node --check scripts/analyze-inactivity.js and node --check scripts/sync-leaderboard.js passed.
• The repository-wide Prettier check still reports pre-existing formatting issues in unrelated files; those were not included in this focused PR.

Checklist

• My code follows the project's coding style.
• I formatted the changed workflow files locally with Prettier.
• This PR uses a feature/* branch; it uses the dedicated non-main branch fix/handle-invalid-users-workflows.
• I performed a self-review of the focused diff.
• The changed workflows introduce no new warnings or errors.
• No documentation update is required.
• The relevant issue is linked with Fixes #542.

[github-actions]

Thank you for submitting a pull request.

Please ensure your changes comply with the project's contribution guidelines and that all workflow checks pass successfully.

Formatting and Branching

• Please confirm you have formatted your code locally using npx prettier --write . before requesting a review.
• Ensure this PR is made from a feature/* branch and not main.

Note: This project is currently maintained by a solo maintainer, so reviews and responses may sometimes take a little time. Thanks for your patience.

[AleksZyro]

Hi! I've addressed the workflow changes for #542 and updated the PR description with the validation details. The changed workflow files pass Prettier and YAML parsing checks. Please let me know if any further adjustments are needed.