Add Calibrate AI Control UI and fleet LLM backend wiring.

Operators toggle Logic gates vs AI Control on Settings, refresh local Ollama models, and save ai_endpoint settings via Calibrate PUT; server scheduler and agent snapshot/command paths support stateless 60s fleet decisions.

agent/client/handlemessage_test.go

@@ -63,6 +63,12 @@ func TestHandleMessageNewJobSetsJob(t *testing.T) {
 	}
 }
 
+func TestHandleMessageAISnapshotRequest(t *testing.T) {
+	c := newTestClient(t)
+	// Should schedule push without panicking (write fails safely with nil conn).
+	c.handleMessage(Message{Type: "ai_snapshot_request", Payload: json.RawMessage("{}")})
+}
+
 func TestHandleMessageNewJobWithErrorRetries(t *testing.T) {
 	c := newTestClient(t)
 	// Error payload — pool not ready yet.