CallToolResult: support EmbeddedResources

Using org.springframework.ai.tool.annotation.Tool with return of io.modelcontextprotocol.spec.McpSchema.CallToolResult does not work for io.modelcontextprotocol.spec.McpSchema.EmbeddedResource;

Limitation is probably inside org.springframework.ai.mcp.McpToolUtils, which only provides ImageContent and TextContent but not io.modelcontextprotocol.spec.McpSchema.EmbeddedResource;

return new SharedSyncToolSpecification(tool, (exchangeOrContext, request) -> {
    try {
       String callResult = toolCallback.call(ModelOptionsUtils.toJsonString(request.arguments()),
             new ToolContext(Map.of(TOOL_CONTEXT_MCP_EXCHANGE_KEY, exchangeOrContext)));
       if (mimeType != null && mimeType.toString().startsWith("image")) {
          return new McpSchema.CallToolResult(List
             .of(new McpSchema.ImageContent(List.of(Role.ASSISTANT), null, callResult, mimeType.toString())),
                false);
       }
       return new McpSchema.CallToolResult(List.of(new McpSchema.TextContent(callResult)), false);
    }
    catch (Exception e) {
       return new McpSchema.CallToolResult(List.of(new McpSchema.TextContent(e.getMessage())), true);
    }
});

Start in org.springframework.ai.mcp.McpToolUtils and trace how CallToolResult content is handled for ImageContent and TextContent. Compare that path with McpSchema.EmbeddedResource and verify that tool results containing embedded resources are supported without regressing the existing content types.