test: add e2e coverage for primitive combo refresh

Adds an E2E test that loads a Primitive wired to KSampler.sampler_name,
presses 'r' (Refresh Node Definitions), and asserts the primitive's
combo options stay a non-empty array containing the connected input's
values. Reproduces the regression this PR fixes — before the fix, the
options array was clobbered with undefined.

browser_tests/assets/primitive/primitive_combo_sampler_name.json

@@ -0,0 +1,58 @@
+{
+  "last_node_id": 2,
+  "last_link_id": 1,
+  "nodes": [
+    {
+      "id": 2,
+      "type": "KSampler",
+      "pos": [521, 41],
+      "size": [315, 262],
+      "flags": {},
+      "order": 1,
+      "mode": 0,
+      "inputs": [
+        { "name": "model", "type": "MODEL", "link": null },
+        { "name": "positive", "type": "CONDITIONING", "link": null },
+        { "name": "negative", "type": "CONDITIONING", "link": null },
+        { "name": "latent_image", "type": "LATENT", "link": null },
+        {
+          "name": "sampler_name",
+          "type": "COMBO",
+          "link": 1,
+          "widget": { "name": "sampler_name" }
+        }
+      ],
+      "outputs": [
+        { "name": "LATENT", "type": "LATENT", "links": null, "shape": 3 }
+      ],
+      "properties": { "Node name for S&R": "KSampler" },
+      "widgets_values": [0, "randomize", 20, 8, "euler", "normal", 1]
+    },
+    {
+      "id": 1,
+      "type": "PrimitiveNode",
+      "pos": [15, 46],
+      "size": [400, 110],
+      "flags": {},
+      "order": 0,
+      "mode": 0,
+      "inputs": [],
+      "outputs": [
+        {
+          "name": "COMBO",
+          "type": "COMBO",
+          "links": [1],
+          "slot_index": 0,
+          "widget": { "name": "sampler_name" }
+        }
+      ],
+      "properties": { "Run widget replace on values": false },
+      "widgets_values": ["euler", "fixed"]
+    }
+  ],
+  "links": [[1, 1, 0, 2, 4, "COMBO"]],
+  "groups": [],
+  "config": {},
+  "extra": { "ds": { "scale": 1, "offset": [0, 0] } },
+  "version": 0.4
+}

browser_tests/tests/primitiveNode.spec.ts

@@ -59,6 +59,54 @@ test.describe('Primitive Node', { tag: ['@screenshot', '@node'] }, () => {
     )
   })
 
+  test('Preserves combo options on the primitive after pressing R to refresh', async ({
+    comfyPage
+  }) => {
+    const getPrimitiveComboState = async () =>
+      comfyPage.page.evaluate(() => {
+        const primitive = window.app!.graph!.nodes.find(
+          (node) => node.type === 'PrimitiveNode'
+        )
+        const widget = primitive?.widgets?.[0]
+        const values = widget?.options?.values
+        return {
+          isArray: Array.isArray(values),
+          length: Array.isArray(values) ? values.length : 0,
+          includesEuler: Array.isArray(values)
+            ? values.includes('euler')
+            : false,
+          value: widget?.value
+        }
+      })
+
+    await comfyPage.workflow.loadWorkflow(
+      'primitive/primitive_combo_sampler_name'
+    )
+
+    await expect
+      .poll(() => getPrimitiveComboState())
+      .toMatchObject({
+        isArray: true,
+        includesEuler: true,
+        value: 'euler'
+      })
+    const before = await getPrimitiveComboState()
+    expect(before.length).toBeGreaterThan(0)
+
+    await comfyPage.canvas.click()
+    await comfyPage.page.keyboard.press('r')
+
+    await expect
+      .poll(() => getPrimitiveComboState())
+      .toMatchObject({
+        isArray: true,
+        includesEuler: true,
+        value: 'euler'
+      })
+    const after = await getPrimitiveComboState()
+    expect(after.length).toBeGreaterThan(0)
+  })
+
   test('Report missing nodes when connect to missing node', async ({
     comfyPage
   }) => {