Address review feedback

- Replace Thread.sleep with sendAndWait in PRVisualization
- Fix top-level statements in multiple-sessions.md (wrap in class)
- Fix .getMessage() → .getData().content() in MultipleSessions.java
- Guard against null readLine() in AccessibilityReport.java
- Add null-safe getCause() + InterruptedException handling in ErrorHandling.java
- Fix paths: jbang commands now include recipe/ prefix
- Fix root README path: cd java/recipe (not java/cookbook/recipe)
- Fix recipe/README.md ralph-loop CLI example

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

@@ -93,10 +93,7 @@ public class PRVisualization {
                 Finally, summarize the PR health - average age, oldest PR, and how many might be considered stale.
                 """, owner, repoName);
 
-            session.send(new MessageOptions().setPrompt(prompt));
-
-            // Wait a bit for initial processing
-            Thread.sleep(10000);
+            session.sendAndWait(new MessageOptions().setPrompt(prompt)).get();
 
             // Interactive loop
             System.out.println("\n💡 Ask follow-up questions or type \"exit\" to quit.\n");
@@ -120,8 +117,7 @@ public class PRVisualization {
                         break;
                     }
 
-                    session.send(new MessageOptions().setPrompt(input));
-                    Thread.sleep(2000); // Give time for response
+                    session.sendAndWait(new MessageOptions().setPrompt(input)).get();
                 }
             }