Add PHPUnit test suite with 64 unit tests (v1.1.1)

PHPUnit 11 + Brain\Monkey for WordPress function mocking. Tests cover
BlockRenderer (28), WidgetRenderer (9), NavWalker (14), and
TemplateController (12). Includes functional WP_HTML_Tag_Processor stub,
CI test job between lint and build-release, prebuild hook gating npm
build on passing tests, and release package exclusions for test files.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

.gitea/workflows/release.yml

@@ -24,10 +24,31 @@ jobs:
         run: |
           find . -name "*.php" -not -path "./vendor/*" -not -path "./node_modules/*" -print0 | xargs -0 -n1 php -l
 
+  test:
+    name: PHPUnit Tests
+    runs-on: ubuntu-latest
+    needs: [lint]
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+
+      - name: Setup PHP
+        uses: shivammathur/setup-php@v2
+        with:
+          php-version: '8.3'
+          extensions: mbstring, xml, dom
+          tools: composer:v2
+
+      - name: Install Composer dependencies
+        run: composer install --no-interaction
+
+      - name: Run PHPUnit
+        run: composer exec -- phpunit
+
   build-release:
     name: Build Release
     runs-on: ubuntu-latest
-    needs: [lint]
+    needs: [test]
     steps:
       - name: Checkout code
         uses: actions/checkout@v4
@@ -120,6 +141,9 @@ jobs:
             -x "${THEME_NAME}/*.log" \
             -x "${THEME_NAME}/*.po~" \
             -x "${THEME_NAME}/*.bak" \
+            -x "${THEME_NAME}/tests/*" \
+            -x "${THEME_NAME}/phpunit.xml.dist" \
+            -x "${THEME_NAME}/.phpunit.cache/*" \
             -x "${THEME_NAME}/views/.gitkeep" \
             -x "${THEME_NAME}/assets/images/.gitkeep" \
             -x "*.DS_Store"
@@ -187,6 +211,14 @@ jobs:
             echo "src/ excluded: OK"
           fi
 
+          # Verify tests excluded
+          if unzip -l "releases/${THEME_NAME}-${VERSION}.zip" | grep -q "${THEME_NAME}/tests/"; then
+            echo "WARNING: tests/ directory should be excluded"
+            exit 1
+          else
+            echo "tests/ excluded: OK"
+          fi
+
       - name: Extract changelog for release notes
         id: changelog
         run: |