Convert testing framework from Karma/Chai/Mocha to Vitest with Playwright (#63)

* Initial plan

* Convert from Karma/Chai/Mocha to Vitest with Playwright browser mode

Co-authored-by: dgreif <[email protected]>

* Fix eslint issues - disable i18n-text rule for tests and fix import extension

Co-authored-by: dgreif <[email protected]>

* Update CI to use Node 22 and 24, drop older versions

Co-authored-by: dgreif <[email protected]>

* Update actions/checkout and actions/setup-node to v4, use Node 24 by default

Co-authored-by: dgreif <[email protected]>

---------

Co-authored-by: copilot-swe-agent[bot] <[email protected]>
Co-authored-by: dgreif <[email protected]>

Author: Copilot

.github/actions/setup/action.yml

@@ -5,9 +5,9 @@ runs:
   using: composite
   steps:
     - name: Set up Node.js
-      uses: actions/setup-node@v2
+      uses: actions/setup-node@v4
       with:
-        node-version: '16.x'
+        node-version: '24.x'
         cache: npm
         registry-url: https://registry.npmjs.org
     - name: Install npm dependencies

.github/workflows/nodejs.yml

@@ -13,13 +13,13 @@ jobs:
 
     strategy:
       matrix:
-        node-version: [16.x, 18.x, 20.x]
+        node-version: [22.x, 24.x]
         # See supported Node.js release schedule at https://nodejs.org/en/about/releases/
 
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v4
     - name: Use Node.js ${{ matrix.node-version }}
-      uses: actions/setup-node@v2
+      uses: actions/setup-node@v4
       with:
         node-version: ${{ matrix.node-version }}
         cache: 'npm'

.github/workflows/publish.yml

@@ -8,10 +8,10 @@ jobs:
   publish-npm:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
-      - uses: actions/setup-node@v3
+      - uses: actions/checkout@v4
+      - uses: actions/setup-node@v4
         with:
-          node-version: 18
+          node-version: 24
           registry-url: https://registry.npmjs.org/
           cache: npm
       - run: npm ci

.github/workflows/release.yml

@@ -18,7 +18,7 @@ jobs:
       new-tag: ${{ steps.new-tag.outputs.new-tag }}
     steps:
       - name: Checkout ref
-        uses: actions/checkout@v2
+        uses: actions/checkout@v4
       - name: Preparation
         uses: ./.github/actions/setup
       - name: Perform last-minute tests
@@ -42,7 +42,7 @@ jobs:
     needs: bump-version
     steps:
       - name: Checkout ref
-        uses: actions/checkout@v2
+        uses: actions/checkout@v4
         with:
           ref: ${{ needs.bump-version.outputs.new-tag }}
       - name: Preparation
@@ -62,7 +62,7 @@ jobs:
     needs: [bump-version, create-release]
     steps:
       - name: Checkout ref
-        uses: actions/checkout@v2
+        uses: actions/checkout@v4
         with:
           ref: ${{ needs.bump-version.outputs.new-tag }}
       - name: Preparation