Add Vitest unit tests for frontend admin UI

.github/workflows/assets_code_analysis.yaml

@@ -24,6 +24,9 @@ jobs:
           - name: Check TypeScript types
             run: npm run typecheck
 
+          - name: Run frontend unit tests
+            run: npm run test:unit:coverage -- --sequence.shuffle
+
           - name: Build for production
             run: npm run build
 

.gitignore

@@ -19,6 +19,7 @@ webpack_stats.json
 ### Behat / Cypress / Front-end testing files
 bin/chromedriver*
 bin/selenium-server-standalone*
+coverage/
 tests/cypress/evidence
 
 ### File-system cruft and temporary files

eslint.config.mjs

@@ -17,15 +17,15 @@ export default [
     // "plugin:vue/recommended" under eslint-plugin-vue 6.
     ...vue.configs['flat/vue2-recommended'],
 
-    // Scoped to assets/**/*.ts so the Vue 2 SFCs, which are still plain JS, keep
+    // Scoped to TypeScript files so the Vue 2 SFCs, which are still plain JS, keep
     // being linted by the vue2 preset above and are not parsed as TypeScript.
     ...tseslint.configs.recommended.map(config => ({
         ...config,
-        files: ['assets/**/*.ts'],
+        files: ['assets/**/*.ts', 'tests/unit/**/*.ts', 'vitest.config.ts'],
     })),
 
     {
-        files: ['assets/**/*.ts'],
+        files: ['assets/**/*.ts', 'tests/unit/**/*.ts', 'vitest.config.ts'],
         rules: {
             // Warn, not error, while TypeScript is confined to the leaf modules.
             // It becomes an error once the components are converted and there is