fix: Correctly structure tool responses

[apappascs]

Refactored list_issues, update_issue, add_issue_comment, and get_issue tools to return their responses in the correct MCP content structure following the spec https://github.com/modelcontextprotocol/specification/blob/main/schema/schema.json#L80

--
tested with spring ai mcp client:

package org.springframework.ai.mcp.samples.github;

import org.springframework.ai.chat.client.ChatClient;
import org.springframework.ai.mcp.client.McpClient;
import org.springframework.ai.mcp.client.McpSyncClient;
import org.springframework.ai.mcp.client.stdio.ServerParameters;
import org.springframework.ai.mcp.client.stdio.StdioServerTransport;
import org.springframework.ai.mcp.spring.McpFunctionCallback;
import org.springframework.boot.CommandLineRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.ConfigurableApplicationContext;
import org.springframework.context.annotation.Bean;

@SpringBootApplication
public class Application {

	public static void main(String[] args) {
		SpringApplication.run(Application.class, args);
	}

	@Bean
	public CommandLineRunner readRepositoryOperations(ChatClient.Builder chatClientBuilder,
			McpSyncClient mcpClient,
			ConfigurableApplicationContext context) {
		return args -> {
			var chatClient = chatClientBuilder
					.defaultFunctions(mcpClient.listTools(null)
							.tools()
							.stream()
							.map(tool -> new McpFunctionCallback(mcpClient, tool))
							.toArray(McpFunctionCallback[]::new))
					.build();


			// 1. list_issues Command (Read Operation on `modelcontextprotocol/servers`):
			String listIssuesCommand = "List the first 10 issues from the repository 'modelcontextprotocol/servers'.";
			System.out.println("COMMAND: " + listIssuesCommand);
			System.out.println("RESPONSE: " + chatClient.prompt(listIssuesCommand).call().content());

			// 2. get_issue Command (Read Operation on `modelcontextprotocol/servers`):
			String getIssueCommand = "Get the details of issue number 10 from the repository 'modelcontextprotocol/servers'.";
			System.out.println("COMMAND: " + getIssueCommand);
			System.out.println("RESPONSE: " + chatClient.prompt(getIssueCommand).call().content());

			// 3. Create Issue Command (Write Operation on `apappascs/test`)
			String createIssueCommand = "Create an issue in the repository 'apappascs/test' with the title 'Test Issue via MCP' and the body 'This is a test issue created using MCP.'";
			System.out.println("COMMAND: " + createIssueCommand);
			System.out.println("RESPONSE: " + chatClient.prompt(createIssueCommand).call().content());

			// 4. update_issue Command (Write Operation on `apappascs/test`):
			String updateIssueCommand = "Update issue number 1 in the repository 'apappascs/test' setting title to 'Updated Title via MCP' and the state to closed.";
			System.out.println("COMMAND: " + updateIssueCommand);
			System.out.println("RESPONSE: " + chatClient.prompt(updateIssueCommand).call().content());

			// 5. add_issue_comment Command (Write Operation on `apappascs/test`):
			String addIssueCommentCommand = "Add the comment 'This is a test comment using MCP' to issue number 1 in the repository 'apappascs/test'.";
			System.out.println("COMMAND: " + addIssueCommentCommand);
			System.out.println("RESPONSE: " + chatClient.prompt(addIssueCommentCommand).call().content());

			context.close();
		};
	}

	@Bean(destroyMethod = "close")
	public McpSyncClient mcpClient() {

		var stdioParams = ServerParameters.builder("node")
				.args("/Users/alex/test_workspace/ai_projects/servers/src/github/dist/index.js")
				.addEnvVar("GITHUB_PERSONAL_ACCESS_TOKEN", System.getenv("GITHUB_PERSONAL_ACCESS_TOKEN"))
				.build();

		// Create the MCP client
		var mcpClient = McpClient.sync(new StdioServerTransport(stdioParams));

		// Initialize the MCP client and log the status
		var initStatus = mcpClient.initialize();
		System.out.println("MCP Initialized: " + initStatus);

		return mcpClient;
	}
}