fix: Java cookbook recipes to compile with copilot-sdk-java 0.2.1-java.1

Fix compilation errors and documentation inaccuracies in Java cookbook
recipes against the actual SDK API:

- MultipleSessions: Replace non-existent destroy() with close()
- AccessibilityReport: Replace non-existent McpServerConfig class with
  Map<String, Object> (the actual type accepted by setMcpServers)
- error-handling.md: Replace non-existent session.addTool(),
  ToolDefinition.builder(), and ToolResultObject with actual SDK APIs
  (ToolDefinition.create(), SessionConfig.setTools(),
  CompletableFuture<Object> return type)

All 7 recipes now compile successfully with jbang build.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

cookbook/copilot-sdk/java/multiple-sessions.md

@@ -48,9 +48,9 @@ public class MultipleSessions {
             session3.sendAndWait(new MessageOptions().setPrompt("How do I initialize a module?")).get();
 
             // Clean up all sessions
-            session1.destroy().get();
-            session2.destroy().get();
-            session3.destroy().get();
+            session1.close();
+            session2.close();
+            session3.close();
         }
     }
 }
@@ -136,7 +136,7 @@ var session = client.createSession(new SessionConfig()
 
 session.sendAndWait(new MessageOptions().setPrompt("Hello!")).get();
 
-session.destroy().get();
+session.close();
 client.stop().get();
 executor.shutdown();
 ```