ci: run PHPUnit in CI (tests exist, were never executed) (#2)

* ci: add PHPUnit workflow that runs the existing test suite

59 tests exist across 8 files but were never running in CI.
This adds a ci.yml with PHP Lint + PHPCS + PHPUnit against WP test
framework on a MySQL service.

Agent-Session: cowork-pr-theme-tests-20260414

* ci: vendor install-wp-tests.sh for the PHPUnit workflow

Standard WP-CLI scaffold script, lightly hardened. Kept in-repo
instead of curl-from-github so CI is reproducible.

Agent-Session: cowork-pr-theme-tests-20260414

* chore: retrigger CI after reviewer fix landed on main

Agent-Session: cowork-pr-theme-tests-20260414

* ci: install subversion before bootstrap (svn no longer preinstalled)

ubuntu-latest dropped svn from the default image. install-wp-tests.sh
still uses svn to fetch the WP test suite from develop.svn.wordpress.org.
Add a step to apt-install subversion before the bootstrap runs.

Agent-Session: cowork-pr-theme-tests-20260414

* ci: skip db creation in install-wp-tests.sh (MySQL service already created it)

Agent-Session: cowork-pr-theme-tests-20260414

* ci: WP_CORE_DIR needs trailing slash for ABSPATH substitution

The wp-tests-config.php substitution copies WP_CORE_DIR into ABSPATH
verbatim, then later WordPress concatenates wp-settings.php. Without
the trailing slash you get /tmp/wordpresswp-settings.php.

Agent-Session: cowork-pr-theme-tests-20260414

.github/workflows/ci.yml

@@ -0,0 +1,112 @@
+name: CI — Lint & Test
+
+# Runs on every PR and every push to main.
+# Three jobs in parallel:
+#   1. PHP Lint — syntax check across supported PHP versions
+#   2. PHPCS — WordPress coding standards (non-blocking during theme rollout)
+#   3. PHPUnit — runs the theme's test suite against the WordPress test framework
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+    branches: [main]
+
+permissions:
+  contents: read
+
+jobs:
+  php-lint:
+    name: PHP Lint (${{ matrix.php }})
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        php: ['7.4', '8.1', '8.3']
+    steps:
+      - uses: actions/checkout@v4
+      - name: Setup PHP ${{ matrix.php }}
+        uses: shivammathur/setup-php@v2
+        with:
+          php-version: ${{ matrix.php }}
+          coverage: none
+      - name: Syntax check all PHP files
+        run: |
+          set -e
+          find . -name '*.php' \
+            -not -path './vendor/*' \
+            -not -path './node_modules/*' \
+            -not -path './.git/*' \
+            -print0 | xargs -0 -n1 -P4 php -l > /dev/null
+
+  phpcs:
+    name: PHPCS (WordPress standards)
+    runs-on: ubuntu-latest
+    continue-on-error: true
+    steps:
+      - uses: actions/checkout@v4
+      - name: Setup PHP
+        uses: shivammathur/setup-php@v2
+        with:
+          php-version: '8.1'
+          coverage: none
+          tools: composer:v2
+      - name: Install dependencies
+        run: composer install --no-progress --no-interaction --prefer-dist
+      - name: Run PHPCS
+        run: vendor/bin/phpcs --standard=.phpcs.xml.dist
+
+  phpunit:
+    name: PHPUnit (PHP ${{ matrix.php }}, WP ${{ matrix.wp }})
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        php: ['8.1']
+        wp: ['latest']
+    services:
+      mysql:
+        image: mysql:8.0
+        env:
+          MYSQL_ROOT_PASSWORD: root
+          MYSQL_DATABASE: wp_tests
+        ports:
+          - 3306:3306
+        options: --health-cmd="mysqladmin ping" --health-interval=10s --health-timeout=5s --health-retries=5
+    steps:
+      - uses: actions/checkout@v4
+      - name: Install subversion
+        # ubuntu-latest no longer ships svn preinstalled. The WP test suite
+        # bootstrap script checks out develop.svn.wordpress.org via svn.
+        run: sudo apt-get update -qq && sudo apt-get install -y --no-install-recommends subversion
+      - name: Setup PHP ${{ matrix.php }}
+        uses: shivammathur/setup-php@v2
+        with:
+          php-version: ${{ matrix.php }}
+          coverage: none
+          tools: composer:v2
+          extensions: mysqli
+      - name: Install composer dependencies
+        run: composer install --no-progress --no-interaction --prefer-dist
+      - name: Wait for MySQL
+        run: |
+          for i in {1..30}; do
+            if mysqladmin ping -h 127.0.0.1 -P 3306 -u root -proot --silent; then
+              echo "MySQL is up"; break
+            fi
+            echo "Waiting for MySQL..."; sleep 2
+          done
+      - name: Install WordPress test suite
+        env:
+          WP_TESTS_DIR: /tmp/wordpress-tests-lib
+          # Trailing slash matters: the bootstrap config substitutes this verbatim into ABSPATH,
+          # then concatenates 'wp-settings.php'. Without the slash you get '/tmp/wordpresswp-settings.php'.
+          WP_CORE_DIR: /tmp/wordpress/
+        run: |
+          chmod +x bin/install-wp-tests.sh
+          # 6th arg = skip-database-creation: the MySQL service already created wp_tests via MYSQL_DATABASE env.
+          bin/install-wp-tests.sh wp_tests root root 127.0.0.1:3306 ${{ matrix.wp }} true
+      - name: Run PHPUnit
+        env:
+          WP_TESTS_DIR: /tmp/wordpress-tests-lib
+        run: vendor/bin/phpunit --colors=always