feat: complete Smartgift AI Laravel unit testing toolkit

- Add 10 core testing guides (setup, AAA principles, PHPUnit/Pest, mocking, anti-patterns, PHP 8.4+, debugging, data factories, advanced edge cases)
- Add 13 component testing guides covering all Laravel layers
- Add standard templates for PHPUnit 10/11 and Pest v2/v3 including ArchitectureTest
- Add Docker smart test runner, dependency installer, and CI/CD templates (GitHub Actions, GitLab CI)
- Add 4 Claude Code skills (laravel-test-setup, laravel-unit-test with --all mode, laravel-test-review, laravel-mock-helper)
- Add single unified installer script (sg-install-unit-testing.sh) with global support, CLI runners, and 1-click updater (sg-test-update)
- Add comprehensive documentation (README.md, USAGE-GUIDE.md)

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

templates/ci/gitlab-ci.yml.template

@@ -0,0 +1,34 @@
+# GitLab CI/CD Pipeline for Laravel Unit Testing
+image: php:8.3-cli-alpine
+
+stages:
+  - test
+
+variables:
+  APP_ENV: "testing"
+  DB_CONNECTION: "sqlite"
+  DB_DATABASE: ":memory:"
+  CACHE_STORE: "array"
+  QUEUE_CONNECTION: "sync"
+  MAIL_MAILER: "array"
+
+cache:
+  key: ${CI_COMMIT_REF_SLUG}
+  paths:
+    - vendor/
+
+unit-test:
+  stage: test
+  before_script:
+    - apk add --no-cache sqlite-libs libzip-dev zip unzip git $PHPIZE_DEPS
+    - pecl install pcov && docker-php-ext-enable pcov
+    - docker-php-ext-install pdo pdo_sqlite zip
+    - curl -sS https://getcomposer.org/installer | php -- --install-dir=/usr/local/bin --filename=composer
+    - composer install --prefer-dist --no-progress --no-interaction
+  script:
+    - php artisan test --testsuite=Unit --coverage --min=80
+  coverage: '/^\s*Lines:\s*\d+.\d+\%/'
+  artifacts:
+    when: always
+    reports:
+      junit: phpunit-report.xml