fix: set agent ID on tool server after /agent switch

SwitchProfile creates a new tool server connection but wasn't calling
SetAgentID on it, causing 'agent ID required' errors when listing tools.

cmd/olliesrv/internal/agent/agent.go

@@ -359,6 +359,9 @@ func (ag *Agent) SwitchProfile(name string) error {
 		return fmt.Errorf("agent %q: %w", name, err)
 	}
 	disp := ag.newToolServer()
+	if disp != nil && ag.id != "" {
+		disp.SetAgentID(ag.id)
+	}
 	env := []string{"OLLIE_SESSION_ID=" + ag.sessionID, "OLLIE_UNAME=" + ag.id}
 	rt := BuildRuntime(cfg, disp, ag.cwd, env, ag.systemPrompt, ag.envBlock)
 	if cfg.Backend != "" {