Add initial MCP Server documentation

- Created `docs/index.md` to serve as the primary entry point for Symfony MCP Server documentation.
- Included sections on quick start, development guides, architecture, testing, API reference, and compatibility.

Author: klapaudius

.gitignore

@@ -31,3 +31,4 @@ testbench.yaml
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+/docs/private/

docs/index.md

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+# Symfony MCP Server Documentation
+
+Welcome to the Symfony MCP Server documentation. This bundle enables developers to seamlessly add a Model Context Protocol (MCP) server to their Symfony applications with support for both SSE and StreamableHTTP transports.
+
+## Quick Start
+
+- [Installation & Configuration](../README.md#installation) - Get started with the bundle
+- [Basic Usage](../README.md#basic-usage) - Learn the fundamentals
+
+## Development Guides
+
+### Tools
+- [Building Tools](building_tools.md) - Create custom MCP tools that LLMs can invoke
+- [Tool Examples & Patterns](building_tools.md#examples) - Common tool implementation patterns
+
+### Prompts  
+- [Building Prompts](building_prompts.md) - Create conversation starters and templates for LLM interactions
+- [Prompt Message Types](building_prompts.md#message-types) - Text, Image, Audio, and Resource messages
+
+### Resources
+- [Building Resources](building_resources.md) - Manage and expose resources to LLM clients
+- [Resource Templates](building_resources.md#templates) - Dynamic resource generation
+
+## Development & Testing
+
+- [Development Guidelines](development_guidelines.md) - Setup, coding standards, and best practices
+- [Testing Commands](../README.md#testing-mcp-tools) - Test tools and prompts without MCP clients
+- [Docker Setup](development_guidelines.md#docker-setup) - Development environment configuration
+
+## Architecture & Advanced Topics
+
+### Core Concepts
+- [Transport Layer](../README.md#why-not-stdio) - SSE vs StreamableHTTP vs STDIO
+- [Pub/Sub Architecture](../README.md#pubsub-architecture-with-adapters) - Message broker and adapter system
+- [Progress Notifications](building_tools.md#progress-notifications) - Real-time updates for long-running operations
+
+### Configuration
+- [Configuration Reference](../src/Resources/config/packages/klp_mcp_server.yaml) - Complete configuration options
+- [Redis Adapter](../README.md#redis-adapter-configuration-optional) - Alternative to cache adapter
+
+## Testing & Debugging
+
+- [MCP Inspector](../README.md#visualizing-with-inspector) - Visual testing interface
+- [Console Commands](../README.md#testing-mcp-tools) - Command-line testing tools
+- [PHPUnit Testing](development_guidelines.md#testing) - Unit and integration tests
+
+## API Reference
+
+### Interfaces
+- **Tools**: `StreamableToolInterface`, `BaseToolInterface` (deprecated)
+- **Prompts**: `PromptInterface`, `PromptMessageInterface`
+- **Resources**: `ResourceInterface`, `ResourceTemplateInterface`
+- **Results**: `ToolResultInterface` with Text, Image, Audio, Resource types
+
+### Services
+- **ProgressNotifier**: Real-time progress updates
+- **PromptRepository**: Prompt management and retrieval
+- **MCPProtocol**: Core protocol implementation
+
+## Requirements & Compatibility
+
+- **PHP**: >=8.2
+- **Symfony**: >=7
+- **Transport**: SSE requires proper web server (not `symfony server:start`)
+
+## Contributing
+
+- [Development Guidelines](development_guidelines.md) - Setup and contribution standards
+- [Issue Tracker](https://github.com/klapaudius/symfony-mcp-server/issues) - Report bugs and request features
+
+---
+
+**Need Help?** Check the [troubleshooting section](development_guidelines.md#troubleshooting) or create an issue on GitHub.