Test: Validate workflow fixes

[kompre]

Purpose

Validate the workflow fixes for race conditions and test triggering.

What This Tests

1. Concurrency Control ✅

• Adding multiple labels ( + ) should only trigger ONE version-bump run
• Previous behavior: 2 separate runs, causing race conditions
• Expected: Single run processes all labels

2. Test Workflow After Version Bump ✅

• Test workflow should automatically run after version bump completes
• Previous behavior: Test never ran (GITHUB_TOKEN commits don't trigger workflows)
• Expected: Test runs via workflow_run trigger, creates required status check

3. Auto-Merge ✅

• After test passes, PR should auto-merge
• Previous behavior: Blocked waiting for test check that never came
• Expected: Auto-merge proceeds automatically

4. Release Workflow ✅

• After merge, release workflow should publish to TestPyPI
• Expected version: 2025.9.0rc1 → 2025.9.0rc2
• Expected: GitHub Release with improved notes using this PR description

Expected Flow

1. Version bump runs (once) → commits new version → enables auto-merge
2. Test workflow triggers automatically (via workflow_run)
3. Test passes → auto-merge proceeds
4. Release workflow publishes to TestPyPI
5. GitHub Release created with this PR's description

🤖 Generated with Claude Code

[github-actions]

✅ Version bumped: 2025.9.1rc1 → 2025.9.1rc2

[github-actions]

✅ Version bumped: 2025.9.1rc2 → 2025.9.1rc3