fix: add getBaseUrl(), PolicyDecision record, and decide(String,int) to PolicyClient

GameSession.java references these APIs which were missing from
PolicyClient, causing 3 compilation errors. Added:
- getBaseUrl() getter
- PolicyDecision record (action, confidence)
- decide(String, int) overload that delegates to decide(JsonObject)

src/main/java/commanderailab/ai/PolicyClient.java

@@ -276,6 +276,22 @@ public class PolicyClient {
     public String getLastError() { return lastError; }
     public int getTotalDecisions() { return totalDecisions; }
     public int getPolicyDecisions() { return policyDecisions; }
+        public String getBaseUrl() { return baseUrl; }
+
+    /** Decision result record for GameSession integration. */
+    public record PolicyDecision(String action, double confidence) {}
+
+        /**
+     * Decide from a JSON string + seat index. Used by GameSession.
+     * Converts to JsonObject and delegates to decide(JsonObject).
+     */
+    public PolicyDecision decide(String stateJson, int seat) {
+        JsonObject state = GSON.fromJson(stateJson, JsonObject.class);
+        state.addProperty("seat", seat);
+        String action = decide(state);
+        return new PolicyDecision(action, 1.0);
+    }
+    
     public int getFallbackDecisions() { return fallbackDecisions; }
     public int getPendingTuples() { return tupleBuffer.size(); }