removed hard coded shader start up

ui/src/components/ConfigEditor.jsx

@@ -50,6 +50,19 @@ function TextField({ config, label, path, setConfig }) {
   );
 }
 
+function OptionalTextField({ config, label, path, placeholder, setConfig }) {
+  return (
+    <Field label={label}>
+      <input
+        type="text"
+        value={readPath(config, path) ?? ""}
+        placeholder={placeholder}
+        onChange={(event) => setConfig((current) => writePath(current, path, event.target.value))}
+      />
+    </Field>
+  );
+}
+
 function InputDeviceField({
   config,
   manualOpen,
@@ -397,7 +410,13 @@ export function ConfigEditor({ onClose }) {
           <h4>Runtime</h4>
           <div className="config-fields config-fields--wide">
             <TextField config={draft} label="Shader library" path="shaderLibrary" setConfig={setDraft} />
-            <TextField config={draft} label="Startup shader" path="runtimeShaderId" setConfig={setDraft} />
+            <OptionalTextField
+              config={draft}
+              label="Startup shader"
+              path="runtimeShaderId"
+              placeholder="restore saved stack"
+              setConfig={setDraft}
+            />
             <NumberField config={draft} label="Server port" min={1} path="serverPort" setConfig={setDraft} />
             <NumberField config={draft} label="Temporal cap" min={0} path="maxTemporalHistoryFrames" setConfig={setDraft} />
             <ToggleField config={draft} label="Auto reload" path="autoReload" setConfig={setDraft} />