feat: realtime lifecycle callbacks and isolated error handling (v27.1.0)

[ArnabChatterjee20k]

Ports the realtime error-handling fix from sdk-generator#1857 to the Android SDK.

What's Changed

• Added: Realtime.onError, onOpen, and onClose lifecycle callbacks
• Fixed: message-handler exceptions are delivered via onError instead of crashing the coroutine
• Fixed: lifecycle callbacks are isolated per connection and cleared on disconnect

onMessage now wraps parsing/dispatch in a try/catch that reports failures through dispatchError (with the AppwriteException code when available). onOpen/onClosing/onFailure dispatch the corresponding lifecycle callbacks, and the callback lists are cleared on disconnect to prevent leakage across connections.

Version is release-tag driven (SDK_VERSION); changelog bumped to 27.1.0.

Scope is realtime-only — no other API surface changed. The e2e coverage for this fix lives in the sdk-generator repo (already merged in #1857); this repo carries no realtime e2e tests.

[greptile-apps]

Greptile Summary

The PR adds public realtime open, close, and error callbacks and routes message-processing exceptions through the error callback. It also clears lifecycle callbacks during disconnect and documents the change as version 27.1.0.

• Adds thread-safe lifecycle callback registries and dispatch helpers.
• Dispatches callbacks from WebSocket listener lifecycle and message-error paths.
• Clears callback registrations during full realtime teardown.
• Updates the changelog for the new realtime behavior.

Confidence Score: 4/5

The PR should not merge until lifecycle callbacks are stored per Realtime connection rather than shared globally.

The new companion-scoped callback lists allow one Realtime instance to receive or erase another instance's lifecycle registrations; the broad Throwable catch is an additional non-blocking exception-boundary concern.

Files Needing Attention: library/src/main/java/io/appwrite/services/Realtime.kt

Important Files Changed

Filename	Overview
library/src/main/java/io/appwrite/services/Realtime.kt	Adds realtime lifecycle/error callbacks, but companion-scoped registries violate per-connection isolation and the catch-all handler suppresses non-recoverable Throwables.
CHANGELOG.md	Documents the 27.1.0 realtime callback and error-isolation changes accurately, although the implementation does not fully provide the stated per-connection isolation.

Prompt To Fix All With AI

### Issue 1
library/src/main/java/io/appwrite/services/Realtime.kt:54-56
**Callback registries cross connections**

If an application creates multiple `Realtime` instances, their lifecycle registrations share these companion-object lists, so one connection dispatches another connection's callbacks and disconnecting either instance clears callbacks for both.

### Issue 2
library/src/main/java/io/appwrite/services/Realtime.kt:443-445
**Throwable catch suppresses termination**

Catching `Throwable` around parsing and application callback dispatch also absorbs cancellation signals and fatal JVM errors, reporting them as ordinary realtime errors and obscuring termination semantics after a non-recoverable failure.

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For each issue above, determine whether it is valid and should be fixed. If so, fix it directly.

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