Add Java SDK cookbook with 7 recipes

Add complete Java cookbook matching the pattern of existing .NET, Go,
Node.js, and Python cookbooks. All 7 recipes included:

- Ralph Loop: Autonomous AI task loops with JBang
- Error Handling: try-with-resources, ExecutionException, timeouts
- Multiple Sessions: Parallel sessions with CompletableFuture
- Managing Local Files: AI-powered file organization
- PR Visualization: Interactive PR age charts
- Persisting Sessions: Save/resume with custom IDs
- Accessibility Report: WCAG reports via Playwright MCP

Each recipe includes both markdown documentation and a standalone
JBang-runnable Java file in recipe/.

cookbook/copilot-sdk/java/recipe/ManagingLocalFiles.java

@@ -0,0 +1,64 @@
+///usr/bin/env jbang "$0" "$@" ; exit $?
+//DEPS com.github:copilot-sdk-java:0.2.1-java.1
+
+import com.github.copilot.sdk.CopilotClient;
+import com.github.copilot.sdk.events.AssistantMessageEvent;
+import com.github.copilot.sdk.events.SessionIdleEvent;
+import com.github.copilot.sdk.events.ToolExecutionCompleteEvent;
+import com.github.copilot.sdk.events.ToolExecutionStartEvent;
+import com.github.copilot.sdk.json.MessageOptions;
+import com.github.copilot.sdk.json.PermissionHandler;
+import com.github.copilot.sdk.json.SessionConfig;
+import java.nio.file.Paths;
+import java.util.concurrent.CountDownLatch;
+
+public class ManagingLocalFiles {
+    public static void main(String[] args) throws Exception {
+        try (var client = new CopilotClient()) {
+            client.start().get();
+
+            // Create session
+            var session = client.createSession(
+                new SessionConfig().setOnPermissionRequest(PermissionHandler.APPROVE_ALL).setModel("gpt-5")).get();
+
+            // Set up event handlers
+            var done = new CountDownLatch(1);
+
+            session.on(AssistantMessageEvent.class, msg -> 
+                System.out.println("\nCopilot: " + msg.getData().content())
+            );
+
+            session.on(ToolExecutionStartEvent.class, evt -> 
+                System.out.println("  → Running: " + evt.getData().toolName())
+            );
+
+            session.on(ToolExecutionCompleteEvent.class, evt -> 
+                System.out.println("  ✓ Completed: " + evt.getData().toolCallId())
+            );
+
+            session.on(SessionIdleEvent.class, evt -> done.countDown());
+
+            // Ask Copilot to organize files - using a safe example folder
+            // For real use, replace with your target folder
+            String targetFolder = args.length > 0 ? args[0] : 
+                System.getProperty("java.io.tmpdir") + "/example-files";
+
+            String prompt = String.format("""
+                Analyze the files in "%s" and show how you would organize them into subfolders.
+
+                1. First, list all files and their metadata
+                2. Preview grouping by file extension
+                3. Suggest appropriate subfolders (e.g., "images", "documents", "videos")
+                
+                IMPORTANT: DO NOT move any files. Only show the plan.
+                """, targetFolder);
+
+            session.send(new MessageOptions().setPrompt(prompt));
+
+            // Wait for completion
+            done.await();
+
+            session.close();
+        }
+    }
+}