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

src/Server/ServerBuilder.php

@@ -38,6 +38,10 @@ use Mcp\Schema\ResourceTemplate;
 use Mcp\Schema\Tool;
 use Mcp\Schema\ToolAnnotations;
 use Mcp\Server;
+use Mcp\Server\Session\InMemorySessionStore;
+use Mcp\Server\Session\SessionFactory;
+use Mcp\Server\Session\SessionFactoryInterface;
+use Mcp\Server\Session\SessionStoreInterface;
 use Psr\Container\ContainerInterface;
 use Psr\EventDispatcher\EventDispatcherInterface;
 use Psr\Log\LoggerInterface;
@@ -65,6 +69,12 @@ final class ServerBuilder
 
     private ?ContainerInterface $container = null;
 
+    private ?SessionFactoryInterface $sessionFactory = null;
+
+    private ?SessionStoreInterface $sessionStore = null;
+
+    private int $sessionTtl = 3600;
+
     private ?int $paginationLimit = 50;
 
     private ?string $instructions = null;
@@ -193,6 +203,18 @@ final class ServerBuilder
         return $this;
     }
 
+    public function setSession(
+        SessionStoreInterface $sessionStore,
+        SessionFactoryInterface $sessionFactory = new SessionFactory(),
+        int $ttl = 3600,
+    ): self {
+        $this->sessionFactory = $sessionFactory;
+        $this->sessionStore = $sessionStore;
+        $this->sessionTtl = $ttl;
+
+        return $this;
+    }
+
     public function setDiscovery(
         string $basePath,
         array $scanDirs = ['.', 'src'],
@@ -292,6 +314,10 @@ final class ServerBuilder
             $discovery->discover($this->discoveryBasePath, $this->discoveryScanDirs, $this->discoveryExcludeDirs);
         }
 
+        $sessionTtl = $this->sessionTtl ?? 3600;
+        $sessionFactory = $this->sessionFactory ?? new SessionFactory();
+        $sessionStore = $this->sessionStore ?? new InMemorySessionStore($sessionTtl);
+
         return new Server(
             jsonRpcHandler: Handler::make(
                 registry: $registry,
@@ -300,6 +326,8 @@ final class ServerBuilder
                 toolCaller: $toolCaller,
                 resourceReader: $resourceReader,
                 promptGetter: $promptGetter,
+                sessionStore: $sessionStore,
+                sessionFactory: $sessionFactory,
                 logger: $logger,
             ),
             logger: $logger,