Addressed PR review comments on liveobjects public API

- PathObjectSubscriptionOptions: validate depth fail-fast per RTPO19c1a,
  throwing AblyException with ErrorInfo(400, 40003) when depth <= 0.
  Depth is now a primitive int; the "no depth / infinite depth" state is
  expressed via a new no-arg constructor (mirrors ably-js `{}` options),
  so no null handling is needed
- LiveMapValue: defensively copy binary payloads on creation and access,
  making the RTLMV3d immutability guarantee real for byte[] values
- ObjectData#getBytes: document that the returned array is the underlying
  message payload and must be treated as read-only
- JsonObjectPathObject/JsonArrayPathObject: reword "primitive resolution"
  javadoc for clarity
- LiveMapPathObject#at: fix javadoc equivalence example to compile
  (get() returns base PathObject, so chain via asLiveMap())

Author: sacOO7

lib/src/main/java/io/ably/lib/object/message/ObjectData.java

@@ -51,7 +51,8 @@ public interface ObjectData {
     @Nullable Boolean getBoolean();
 
     /**
-     * Returns the binary value.
+     * Returns the binary value. The returned array is the underlying message
+     * payload and is not defensively copied; callers must treat it as read-only.
      *
      * <p>Spec: OD2c
      *

lib/src/main/java/io/ably/lib/object/path/PathObjectSubscriptionOptions.java

@@ -1,5 +1,7 @@
 package io.ably.lib.object.path;
 
+import io.ably.lib.types.AblyException;
+import io.ably.lib.types.ErrorInfo;
 import org.jetbrains.annotations.Nullable;
 
 /**
@@ -13,12 +15,32 @@ public final class PathObjectSubscriptionOptions {
     private final Integer depth;
 
     /**
-     * Creates options with the given {@code depth}.
+     * Creates options with no {@code depth} set: there is no depth limit, and
+     * changes at any depth within nested children trigger the listener.
+     * Equivalent to passing a {@code null} depth.
+     *
+     * <p>Spec: RTPO19c1
+     */
+    public PathObjectSubscriptionOptions() {
+        this.depth = null;
+    }
+
+    /**
+     * Creates options with the given {@code depth}. For infinite depth, use the
+     * no-arg constructor {@link #PathObjectSubscriptionOptions()} instead.
+     *
+     * <p>Spec: RTPO19c1, RTPO19c1a
      *
      * @param depth how many levels of path nesting below the subscribed path should
-     *              trigger the listener; must be a positive integer if provided
+     *              trigger the listener; must be a positive integer
+     * @throws AblyException with {@code statusCode} 400 and {@code code} 40003 if
+     *                       {@code depth} is not a positive integer
      */
-    public PathObjectSubscriptionOptions(@Nullable Integer depth) {
+    public PathObjectSubscriptionOptions(int depth) throws AblyException {
+        if (depth <= 0) {
+            throw AblyException.fromErrorInfo(
+                new ErrorInfo("Subscription depth must be greater than 0 or omitted for infinite depth", 400, 40003));
+        }
         this.depth = depth;
     }
 

lib/src/main/java/io/ably/lib/object/path/types/JsonArrayPathObject.java

@@ -8,7 +8,7 @@
  * A {@link PathObject} whose underlying value is expected to be a {@link JsonArray}.
  *
  * <p>This is a terminal type. {@link PathObject#instance()} returns {@code null}
- * because a primitive resolution does not produce a wrapped LiveObject; navigation
+ * because this resolution does not produce a wrapped LiveObject instance; navigation
  * via {@code at(...)} is not available here because it is only defined on
  * {@code LiveMapPathObject}. Only {@link #value()} and the inherited read APIs are
  * useful here.

lib/src/main/java/io/ably/lib/object/path/types/JsonObjectPathObject.java

@@ -8,7 +8,7 @@
  * A {@link PathObject} whose underlying value is expected to be a {@link JsonObject}.
  *
  * <p>This is a terminal type. {@link PathObject#instance()} returns {@code null}
- * because a primitive resolution does not produce a wrapped LiveObject; navigation
+ * because this resolution does not produce a wrapped LiveObject instance; navigation
  * via {@code at(...)} is not available here because it is only defined on
  * {@code LiveMapPathObject}. Only {@link #value()} and the inherited read APIs are
  * useful here.

lib/src/main/java/io/ably/lib/object/path/types/LiveMapPathObject.java

@@ -46,7 +46,7 @@ public interface LiveMapPathObject extends PathObject {
      *
      * <p>This is purely navigational - no resolution against the LiveObjects graph is
      * performed by this call. {@code liveMapPath.at("a.b.c")} is equivalent to
-     * {@code liveMapPath.get("a").get("b").get("c")}.
+     * {@code liveMapPath.get("a").asLiveMap().get("b").asLiveMap().get("c")}.
      *
      * <p>Available only on {@code LiveMapPathObject} because deeper navigation is only
      * meaningful when the current resolved value is a {@code LiveMap}. To traverse from

lib/src/main/java/io/ably/lib/object/value/LiveMapValue.java

@@ -183,7 +183,8 @@ public static LiveMapValue of(@NotNull Boolean value) {
     }
 
     /**
-     * Creates a LiveMapValue from a Binary.
+     * Creates a LiveMapValue from a Binary. The array is copied, so later
+     * modifications to {@code value} do not affect the created LiveMapValue.
      *
      * @param value the binary value
      * @return a LiveMapValue containing the binary
@@ -290,19 +291,19 @@ private static final class BinaryValue extends LiveMapValue {
         private final byte[] value;
 
         BinaryValue(byte @NotNull [] value) {
-            this.value = value;
+            this.value = value.clone();
         }
 
         @Override
         public @NotNull Object getValue() {
-            return value;
+            return value.clone();
         }
 
         @Override
         public boolean isBinary() { return true; }
 
         @Override
-        public byte @NotNull [] getAsBinary() { return value; }
+        public byte @NotNull [] getAsBinary() { return value.clone(); }
     }
 
     /**