fix: add timeout and error handling to LLM call in scoreHint

Co-authored-by: aider (openai//models/qwen2.5-coder-32b-instruct-q4_k_m.gguf) <aider@aider.chat>

src/puzzle/HintJob.java

@@ -3,6 +3,8 @@ package puzzle;
 import java.io.*;
 import java.nio.charset.StandardCharsets;
 import java.sql.*;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.TimeoutException;
 
 public class HintJob {
    
@@ -120,7 +122,13 @@ public class HintJob {
       try (var in = p.getInputStream()) {
          out = new String(in.readAllBytes(), StandardCharsets.UTF_8);
       }
-      p.waitFor();
+      if (!p.waitFor(30, TimeUnit.SECONDS)) {
+         p.destroy();
+         throw new TimeoutException("LLM call timed out");
+      }
+      if (p.exitValue() != 0) {
+         throw new IOException("LLM call failed with exit code " + p.exitValue());
+      }
       
       var guessed = jsonGetString(out, "content");
       if (guessed != null) guessed = guessed.trim().toUpperCase().replaceAll("[^A-Z]", "");