fix(controller): don't fail entire call to list agents based on results for one/more agents

[onematchfox]

Currently, every agent must exist in both Kubernetes and the database for this call to succeed. Thus, if for whatever reason an agent fails to reconcile on creation, any calls to this endpoint will fail. This, in turn, breaks all agents in the UI. This solution is a bit of a hack/workaround, and I do think issues should be surfaced; however, it at least ensures that the UI stays functional in this scenario for the time being.

$ k get agents                
NAME           ACCEPTED   MODELCONFIG
k8s-agent      True       default-model-config
promql-agent   False      default-model-config

[Copilot]

Pull Request Overview

This PR fixes an issue where the list agents endpoint would fail completely if any single agent couldn't be loaded from the database, preventing the UI from displaying any agents. The fix changes the error handling to skip problematic agents and continue processing the rest, ensuring the API remains functional even when some agents have reconciliation issues.

• Replaces hard failure with error logging and continuation for database lookup failures
• Adds TODO comment acknowledging this is a temporary workaround
• Maintains UI functionality by returning available agents instead of failing entirely

[Copilot]

The error logging should include more context about the specific error type to help with debugging. Consider logging the error type or checking if it's a specific type of error (e.g., not found vs connection error) before deciding to continue.

Suggested change

	log.Error(err, "failed to load agent from database", "agent", teamRef)
	if k8serrors.IsNotFound(err) {
	log.Error(err, "agent not found in database", "agent", teamRef)
	} else if strings.Contains(err.Error(), "connection") {
	log.Error(err, "database connection error while loading agent", "agent", teamRef)
	} else {
	log.Error(err, "unexpected error while loading agent from database", "agent", teamRef)
	}

[onematchfox]

Problematic code was commented out in #671