[ISSUE-495]: Fix access data permission prompt and Core Data crash during setup

[luca-borrione]

Fixes #495

Primary Fix: Access Data Permission Prompt

The "access data" permission prompt was appearing because:

• Trailer uses Apple Events to communicate between the main app and its launcher helper
• macOS requires explicit permission declarations for Apple Events access

Without proper NSAppleEventsUsageDescription entries, the system shows a generic "access data" prompt.
These changes provide clear, user-friendly explanations for why the app needs Apple Events access, replacing the confusing generic permission prompt with proper context.

The launcher also needs com.apple.security.automation.apple-events entitlement for automation permissions

Secondary Fix: Core Data Crash in SetupAssistant

While testing the permission fix, discovered and fixed a crash in SetupAssistant.swift that occurred during server setup:

The app crashed with assert(!objectID.isTemporaryID) when trying to set auth tokens on newly created ApiServer objects.

Solution:

Ensures the server has a permanent Core Data object ID before setting the auth token, preventing the assertion failure.

Test

Started from Trailer 1.8.14 (current main a9d2353) on Mac Sequoia 15.6

[ptsochantaris]

Thanks so much for this! That permission requirement was extremely well hidden, as a Trailer user I'm definitely grateful for not having that noise anymore.