feat: add advanced architecture, documentation, and coverage improvements (#65)

* fix(style): resolve PHPCS line-length warnings in source files

* fix(style): resolve PHPCS line-length warnings in test files

* feat(audit): add structured audit logging with ErrorContext and AuditContext

- ErrorContext: standardized error information with sensitive data sanitization
- AuditContext: structured context for audit entries with operation types
- StructuredAuditLogger: enhanced audit logger wrapper with timing support

* feat(recovery): add recovery mechanism for failed masking operations

- FailureMode enum: FAIL_OPEN, FAIL_CLOSED, FAIL_SAFE modes
- RecoveryStrategy interface and RecoveryResult value object
- RetryStrategy: exponential backoff with configurable attempts
- FallbackMaskStrategy: type-aware fallback values

* feat(strategies): add CallbackMaskingStrategy for custom masking logic

- Wraps custom callbacks as MaskingStrategy implementations
- Factory methods: constant(), hash(), partial() for common use cases
- Supports exact match and prefix match for field paths

* docs: add framework integration guides and examples

- symfony-integration.md: Symfony service configuration and Monolog setup
- psr3-decorator.md: PSR-3 logger decorator pattern implementation
- framework-examples.md: CakePHP, CodeIgniter 4, Laminas, Yii2, PSR-15
- docker-development.md: Docker development environment guide

* chore(docker): add Docker development environment

- Dockerfile: PHP 8.2-cli-alpine with Xdebug for coverage
- docker-compose.yml: development services with volume mounts

* feat(demo): add interactive GDPR pattern tester playground

- PatternTester.php: pattern testing utility with strategy support
- index.php: web API endpoint with JSON response handling
- playground.html: interactive web interface for testing patterns

* docs(todo): update with completed medium priority items

- Mark all PHPCS warnings as fixed (81 → 0)
- Document new Audit and Recovery features
- Update test count to 1,068 tests with 2,953 assertions
- Move remaining items to low priority

* feat: add advanced architecture, documentation, and coverage improvements

- Add architecture improvements:
  - ArrayAccessorInterface and DotArrayAccessor for decoupled array access
  - MaskingOrchestrator for single-responsibility masking coordination
  - GdprProcessorBuilder for fluent configuration
  - MaskingPluginInterface and AbstractMaskingPlugin for plugin architecture
  - PluginAwareProcessor for plugin hook execution
  - AuditLoggerFactory for instance-based audit logger creation

- Add advanced features:
  - SerializedDataProcessor for handling print_r/var_export/serialize output
  - KAnonymizer with GeneralizationStrategy for GDPR k-anonymity
  - RetentionPolicy for configurable data retention periods
  - StreamingProcessor for memory-efficient large log processing

- Add comprehensive documentation:
  - docs/performance-tuning.md - benchmarking, optimization, caching
  - docs/troubleshooting.md - common issues and solutions
  - docs/logging-integrations.md - ELK, Graylog, Datadog, etc.
  - docs/plugin-development.md - complete plugin development guide

- Improve test coverage (84.41% → 85.07%):
  - ConditionalRuleFactoryInstanceTest (100% coverage)
  - GdprProcessorBuilderEdgeCasesTest (100% coverage)
  - StrategyEdgeCasesTest for ReDoS detection and type parsing
  - 78 new tests, 119 new assertions

- Update TODO.md with current statistics:
  - 141 PHP files, 1,346 tests, 85.07% line coverage

* chore: tests, update actions, sonarcloud issues

* chore: rector

* fix: more sonarcloud fixes

* chore: more fixes

* refactor: copilot review fix

* chore: rector

docker/Dockerfile

@@ -0,0 +1,37 @@
+FROM php:8.2-cli-alpine
+
+# Install system dependencies
+RUN apk add --no-cache \
+    git \
+    unzip \
+    curl \
+    libzip-dev \
+    icu-dev \
+    && docker-php-ext-install \
+    zip \
+    intl \
+    pcntl
+
+# Install Composer
+COPY --from=composer:2 /usr/bin/composer /usr/bin/composer
+
+# Install and configure Xdebug for code coverage
+RUN apk add --no-cache $PHPIZE_DEPS \
+    && pecl install xdebug \
+    && docker-php-ext-enable xdebug \
+    && echo "xdebug.mode=coverage,debug" >> /usr/local/etc/php/conf.d/docker-php-ext-xdebug.ini \
+    && echo "xdebug.client_host=host.docker.internal" >> /usr/local/etc/php/conf.d/docker-php-ext-xdebug.ini
+
+# Set working directory
+WORKDIR /app
+
+# Set recommended PHP settings for development and create non-root user
+RUN echo "memory_limit=512M" >> /usr/local/etc/php/conf.d/docker-php-memory.ini \
+    && echo "error_reporting=E_ALL" >> /usr/local/etc/php/conf.d/docker-php-errors.ini \
+    && echo "display_errors=On" >> /usr/local/etc/php/conf.d/docker-php-errors.ini \
+    && addgroup -g 1000 developer \
+    && adduser -D -u 1000 -G developer developer
+
+USER developer
+
+CMD ["php", "-v"]