chore(tests): Mock LLM in tests for PRs

This saves time when testing on CPU which is the only sensible thing
to do on GitHub CI for PRs. For releases or once the commit is merged
we could use an external runner with GPU or just wait.

Signed-off-by: Richard Palethorpe <io@richiejp.com>

core/agent/agent.go

@@ -29,7 +29,7 @@ type Agent struct {
 	sync.Mutex
 	options   *options
 	Character Character
-	client    *openai.Client
+	client    llm.LLMClient
 	jobQueue  chan *types.Job
 	context   *types.ActionContext
 
@@ -63,7 +63,12 @@ func New(opts ...Option) (*Agent, error) {
 		return nil, fmt.Errorf("failed to set options: %v", err)
 	}
 
-	client := llm.NewClient(options.LLMAPI.APIKey, options.LLMAPI.APIURL, options.timeout)
+	var client llm.LLMClient
+	if options.llmClient != nil {
+		client = options.llmClient
+	} else {
+		client = llm.NewClient(options.LLMAPI.APIKey, options.LLMAPI.APIURL, options.timeout)
+	}
 
 	c := context.Background()
 	if options.context != nil {
@@ -125,6 +130,11 @@ func (a *Agent) SharedState() *types.AgentSharedState {
 	return a.sharedState
 }
 
+// LLMClient returns the agent's LLM client (for testing)
+func (a *Agent) LLMClient() llm.LLMClient {
+	return a.client
+}
+
 func (a *Agent) startNewConversationsConsumer() {
 	go func() {
 		for {