Fix/mirror limits optional chaining

[tharu-jwd]

Description

Add optional chaining to this.config.limits?.event in StaticMirroringWorker.canAcceptEvent()

Related Issue

Fixes #567

Motivation and Context

Mirror.limits is typed as optional but was accessed without optional chaining. When a mirror entry has no limits block configured, this throws a TypeError inside the message handler which gets swallowed by the surrounding try/catch. So the mirror connects and subscribes fine, but silently drops every incoming event.

How Has This Been Tested?

Manually configured a mirror entry without a limits block and confirmed events are stored correctly after the fix.

Screenshots (if appropriate):

N/A

Types of changes

• Non-functional change (docs, style, minor refactor)
• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my code changes.
• I added a changeset, or this is docs-only and I added an empty changeset.
• All new and existing tests passed.