fix: check topic actor status before publishing events

[mattjohnsonpint]

Attempt to fix #917

[linear]

MOD-6 remote send failed, actor is not alive

[Copilot]

Pull Request Overview

A fix to prevent publishing events when the topic actor is not running and update the changelog accordingly

• Guard added in PublishAgentEvent to skip publishing if the topic actor has stopped
• Warning logged instead of error when skipping event publication during shutdown
• Changelog updated under an UNRELEASED section to document the fix

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
runtime/actors/agents.go	Added a check for topicActor.IsRunning() with a warning and early return
CHANGELOG.md	Documented the new fix under an UNRELEASED section

Comments suppressed due to low confidence (2)

runtime/actors/agents.go:270

• Add a unit test covering the case when the topic actor is not running to verify that events are correctly skipped.

	if !topicActor.IsRunning() {

CHANGELOG.md:7

• Use a level-2 markdown header (e.g., "## UNRELEASED") to match the formatting of other release entries in the changelog.

UNRELEASED