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/recipe/AccessibilityReport.java

@@ -43,11 +43,12 @@ public class AccessibilityReport {
             client.start().get();
 
             // Configure Playwright MCP server for browser automation
-            var mcpConfig = new McpServerConfig()
-                .setType("local")
-                .setCommand("npx")
-                .setArgs(List.of("@playwright/mcp@latest"))
-                .setTools(List.of("*"));
+            Map<String, Object> mcpConfig = Map.of(
+                "type", "local",
+                "command", "npx",
+                "args", List.of("@playwright/mcp@latest"),
+                "tools", List.of("*")
+            );
 
             var session = client.createSession(
                 new SessionConfig()