fix: Rokt Callback should be Called on Main

[BrandonStalnaker]

Background

• Placement lifecycle callbacks (onLoad, onUnLoad, loading indicators, onEmbeddedSizeChange) are still invoked by Rokt’s native layer when work completes, and those invocations can occur on a background queue. Integrators often update Auto Layout, call layoutIfNeeded(), or publish to UI-bound streams from those callbacks, which is only safe on the main thread and can contribute to rare UIKit crashes or instability in production.

What Has Changed

• Before forwarding to the kit, MPRokt now wraps a non-empty MPRoktEventCallback so each set handler runs on the main queue: synchronous execution when already on the main thread, otherwise dispatch_async to the main queue. onEmbeddedSizeChange copies the placement string before async dispatch so arguments stay valid.
• Nil callbacks and callbacks with all properties nil are unchanged (still forwarded as nil where appropriate).
• Public API documentation in MPRokt.h states that these callbacks are delivered on the main queue.
• Unit tests were updated: the expanded selectPlacements test no longer asserts block identity (wrapping produces new blocks), and testSelectPlacementsMarshallsCallbacksToMainThread verifies that invoking the forwarded onLoad from a background queue runs the app’s handler on the main thread.

Checklist

• I have performed a self-review of my own code.
• I have made corresponding changes to the documentation.
• I have added tests that prove my fix is effective or that my feature works.
• I have tested this locally.

[cursor]

PR Summary

Medium Risk
Changes the threading behavior of selectPlacements callbacks by wrapping and re-dispatching blocks, which could affect callback timing/order and surface latent race conditions, but is limited to Rokt placement lifecycle handlers.

Overview
Rokt placement lifecycle callbacks are now main-thread safe. MPRokt wraps any provided MPRoktEventCallback before forwarding to the Rokt kit so each non-nil handler (onLoad, onUnLoad, loading indicator callbacks, onEmbeddedSizeChange) executes synchronously on the main thread when already there, otherwise via dispatch_async to the main queue (copying onEmbeddedSizeChange args before dispatch).

Updates public header docs to guarantee main-queue delivery, and adjusts/adds unit tests to validate wrapping (block identity changes) and that invoking the forwarded callback from a background queue runs the original handler on the main thread.

^{Written by Cursor Bugbot for commit 8aa7e7c. This will update automatically on new commits. Configure here.}

[github-actions]

📦 SDK Size Impact Report

Measures how much the SDK adds to an app's size (with-SDK minus without-SDK).

Metric	Target Branch	This PR	Change
App Bundle Impact	1.82 MB	1.82 MB	+4 KB
Executable Impact	896 bytes	896 bytes	+N/A
XCFramework Size	9.49 MB	9.50 MB	+12 KB

➡️ SDK size impact change is minimal.

Raw measurements

Target branch (main):

{"baseline_app_size_kb":84,"baseline_executable_size_bytes":75464,"with_sdk_app_size_kb":1944,"with_sdk_executable_size_bytes":76360,"sdk_impact_kb":1860,"sdk_executable_impact_bytes":896,"xcframework_size_kb":9720}

This PR:

{"baseline_app_size_kb":84,"baseline_executable_size_bytes":75464,"with_sdk_app_size_kb":1948,"with_sdk_executable_size_bytes":76360,"sdk_impact_kb":1864,"sdk_executable_impact_bytes":896,"xcframework_size_kb":9732}

[nickolas-dimitrakas]

LGTM