Merge pull request #32915 from Azquelt/feature-mcp-server-snapshot

Merge changes from MCP feature branch

Author: Azquelt

dev/io.openliberty.mcp.internal/src/io/openliberty/mcp/internal/McpTransport.java

@@ -161,6 +161,7 @@ public <T> T getParams(Class<T> type) {
      */
     public void sendResponse(Object result) {
         McpResponse mcpResponse = new McpResultResponse(mcpRequest.id(), result);
+        res.setContentType("application/json");
         jsonb.toJson(mcpResponse, writer);
     }
 
@@ -193,6 +194,7 @@ public void sendError(Exception e) throws IOException {
      */
     public void sendJsonRpcException(JSONRPCException e) {
         McpResponse mcpResponse = new McpErrorResponse(mcpRequest == null ? new McpRequestId("") : mcpRequest.id(), e);
+        res.setContentType("application/json");
         jsonb.toJson(mcpResponse, writer);
     }