…ance class

…assessment doc

- 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())

…al-public-api

[LiveObjects] Implement path-based LiveObjects public API

…ccessor

Introduce the public, strongly-typed, path-based LiveObjects entry point on a
realtime channel, accessed via `channel.object`.

- RealtimeObject: exposes `get()` returning the root LiveMapPathObject, and
  extends ObjectStateChange to subscribe to objects sync-state events
  (on/off/offAll).
- ObjectStateChange / ObjectStateEvent: the SYNCING/SYNCED sync-state
  subscription API surface.
- ChannelBase.object: a public field providing `channel.object` access. When
  the LiveObjects plugin is not installed, the field is assigned
  RealtimeObject.Unavailable - a null-object guard whose methods fail fast with
  a clear plugin-missing error (statusCode 400, code 40019) instead of an NPE,
  keeping the `channel.object.<method>()` syntax consistent in both cases.

The plugin-present branch is intentionally left as a TODO until the LiveObjects
plugin exposes the new io.ably.lib.object.RealtimeObject type (getInstance
currently returns the legacy io.ably.lib.objects.RealtimeObjects).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

…ture

- Replaced ObjectsSubscription import with Subscription as per requirement

…tion-for-path-based-interfaces

[AIT-928] feat(liveobjects): add path-based RealtimeObject and channel.object accessor

…mplementation' into chore/liveobjects-add-basic-implementation

… relevant

error codes under `Errors.kt`

…onArray

- Marked PathObject#getValue as nullable when value doesn't exist at given path

… to ably-js