feat(ci): auto-cancel superseded workflow runs

Add concurrency group to automatically cancel in-progress workflow runs
when a new push is made to the same branch. This prevents wasted CI
resources and provides faster feedback on the latest changes.

Concurrency group: workflow name + git ref (branch)
Behavior: New push cancels any in-progress runs for that branch

Author: pythoninthegrass

.github/workflows/test.yml

@@ -6,6 +6,11 @@ on:
   pull_request:
     branches: [main, tauri-migration]
 
+# Cancel in-progress runs when a new push supersedes them
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
 jobs:
   # Frontend E2E tests with Playwright
   playwright-tests: