chore: adds CLAUDE file

Author: JasonTheAdams

CLAUDE.md

@@ -0,0 +1,65 @@
+# CLAUDE.md
+
+This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
+
+## Common Development Commands
+
+### Linting and Code Quality
+- **Run all linting checks**: `composer lint` (runs both PHPCS and PHPStan)
+- **Run PHP CodeSniffer**: `composer phpcs`
+- **Fix code style issues**: `composer phpcbf`
+- **Run PHPStan static analysis**: `composer phpstan`
+
+### Testing
+- **Run PHPUnit tests**: `composer phpunit`
+
+### Dependencies
+- **Install dependencies**: `composer install`
+- **Update dependencies**: `composer update`
+
+## High-level Architecture
+
+This project is a PHP AI Client SDK designed to provide a provider-agnostic API for interacting with various generative AI models. The architecture has several key design principles:
+
+### API Layers
+
+1. **Implementer API**: For developers using the SDK to add AI features to their applications
+   - Fluent API: Chain methods for readable, declarative code (e.g., `AiClient::prompt('...')->generateText()`)
+   - Traditional API: Method-based approach with arrays of arguments
+   
+2. **Extender API**: For developers adding new providers, models, or extending functionality
+   - Provider Registry system for managing available AI providers
+   - Model discovery based on capabilities and requirements
+
+### Core Concepts
+
+- **Provider Agnostic**: Abstracts away provider-specific details, allowing code to work with any AI provider (Google, OpenAI, Anthropic, etc.)
+- **Capability-Based Model Selection**: Models can be discovered and selected based on their supported capabilities (text generation, image generation, etc.) and options (input modalities, output formats, etc.)
+- **Uniform Data Structures**: Consistent message formats, file representations, and results across all providers
+- **Modality Support**: Designed to support arbitrary combinations of input/output modalities (text, image, audio, video)
+
+### Namespace Structure
+
+The codebase follows a structured namespace hierarchy under `WordPress\AiClient`:
+- `Builders`: Fluent API builders (PromptBuilder, MessageBuilder)
+- `Embeddings`: Embedding-related data structures
+- `Files`: File handling contracts and implementations
+- `Messages`: Message DTOs and enums
+- `Operations`: Long-running operation support
+- `Providers`: Provider system with contracts, models, and registry
+- `Results`: Result data structures and transformations
+- `Tools`: Function calling and tool support
+- `Util`: Utility classes for common operations
+
+### Key Design Patterns
+
+- **Interface Segregation**: Separate interfaces for different model capabilities (TextGenerationModelInterface, ImageGenerationModelInterface, etc.)
+- **Composition over Inheritance**: Models compose capabilities through interfaces rather than inheritance
+- **DTO Pattern**: Data Transfer Objects for messages, results, and configurations with JSON schema support
+- **Builder Pattern**: Fluent builders for constructing prompts and messages
+
+### PHP Compatibility
+
+- Minimum PHP version: 7.4
+- Follows PER Coding Style
+- Uses type hints wherever possible within PHP 7.4 constraints