feat(server): Rework transport architecture and add StreamableHttpTransport (#49)

* feat(server): Rework transport architecture and add StreamableHttpTransport

- `Server::connect()` no longer contains a processing loop.
- `TransportInterface` is updated with `setMessageHandler()` and `listen()`.
- `StdioTransport` is updated to implement the new interface.
- A new, minimal `StreamableHttpTransport` is added for stateless HTTP.

* refactor(server): use  event-driven message handling

* feat(server): Introduce a formal session management system

* fix: ensure session elements are preserved when building server (regression from #46)

* refactor: consolidate HTTP example to use shared dependencies

* feat(server): Enhance message handling with session support

- Updated `TransportInterface` to use `onMessage` for handling incoming messages with session IDs.
- Refactored `Server`, `Handler`, and transport classes to accommodate session management using `Uuid`.
- Introduced methods for creating sessions with auto-generated and specific UUIDs in `SessionFactory` and `SessionFactoryInterface`.

* feat(server): Integrate session management in message handling

- Added session support to the `Server` and `Handler` classes, allowing for session data to be managed during message processing.
- Updated `TransportInterface` to include session context in the `send` method.
- Refactored various request handlers to utilize session information, ensuring proper session handling for incoming requests.
- Introduced a file-based session store for persistent session data management

* feat: Update session builder method to use set* instead of with*

* feat: Fix test compatibility with new session management architecture

* chore: apply code style fixes

* fix: remove deprecated SSE transport and resolve PHPStan issues

examples/10-simple-http-transport/README.md

@@ -0,0 +1,24 @@
+# HTTP MCP Server Example
+
+This example demonstrates how to use the MCP SDK with HTTP transport using the StreamableHttpTransport. It provides a complete HTTP-based MCP server that can handle JSON-RPC requests over HTTP POST.
+
+## Usage
+
+**Step 1: Start the HTTP server**
+
+```bash
+cd examples/10-simple-http-transport
+php -S localhost:8000 server.php
+```
+
+**Step 2: Connect with MCP Inspector**
+
+```bash
+npx @modelcontextprotocol/inspector http://localhost:8000
+```
+
+## Available Features
+
+- **Tools**: `current_time`, `calculate`
+- **Resources**: `info://server/status`, `config://app/settings`
+- **Prompts**: `greet`