Refactor transport layer abstraction

src/Transport/HttpTransport.php

@@ -24,7 +24,7 @@
  * Origin checks, complex ACK logic, and related session properties have been removed.
  * It primarily focuses on basic JSON-RPC via POST.
  */
-class HttpTransport extends AbstractTransport
+class HttpTransport implements TransportInterface
 {
     // Kept essential properties for basic POST JSON-RPC.
     /** @var ResponseInterface|null The PSR-7 response object being prepared. */
@@ -266,4 +266,20 @@
         }
         return $this->response;
     }
+
+    /**
+     * Indicates a preference for using Server-Sent Events (SSE) for streaming responses, if applicable.
+     *
+     * Transports that support SSE (like HttpTransport) can use this hint to switch
+     * their response mode. Other transports can ignore this.
+     *
+     * @param bool $prefer True to prefer SSE, false otherwise.
+     */
+    public function preferSseStream(bool $prefer = true): void
+    {
+        // Default implementation does nothing, to be overridden by transports that support SSE.
+        // In a real HttpTransport that supports SSE, this method would set a flag
+        // to change response content-type and formatting in the send() method.
+        // For this simplified version, it remains a no-op.
+    }
 }

src/Transport/StdioTransport.php

@@ -13,7 +13,7 @@
  * Implements a transport using STDIN, STDOUT, and STDERR for line-based JSON messaging.
  * Each JSON-RPC message (or batch of messages) is expected to be on a single line.
  */
-class StdioTransport extends AbstractTransport
+class StdioTransport implements TransportInterface
 {
     /** @var resource The standard input stream. */
     private $stdin;
@@ -203,4 +203,15 @@
     {
         return false;
     }
+
+    /**
+     * Indicates a preference for using Server-Sent Events (SSE) for streaming responses, if applicable.
+     * StdioTransport does not support SSE, so this is a no-op.
+     *
+     * @param bool $prefer True to prefer SSE, false otherwise.
+     */
+    public function preferSseStream(bool $prefer = true): void
+    {
+        // StdioTransport does not support SSE.
+    }
 }

src/Transport/TransportInterface.php

@@ -50,16 +50,6 @@ public function receive(): ?array;
      */
     public function send(JsonRpcMessage|array $message): void;
 
-    /**
-     * Logs a message specific to the transport's operation.
-     *
-     * Example: For StdioTransport, this might write to STDERR.
-     * For HttpTransport, it might use a PSR-3 logger if integrated.
-     *
-     * @param string $message The message to log.
-     */
-    public function log(string $message): void;
-
     /**
      * Checks if the transport connection is considered closed.
      *