test(front): add e2e test for theme CSS token integration

Verify that Cunningham contextual tokens resolve at runtime and that
the scheduler toolbar no longer uses hardcoded white background,
confirming the theme CSS chain works end-to-end.

src/frontend/apps/e2e/__tests__/calendar.test.ts

@@ -230,4 +230,29 @@ test.describe('Calendar Application', () => {
       await expect(focusedElement).toBeDefined()
     })
   })
+
+  test.describe('Theme Integration', () => {
+    test('calendar uses contextual CSS tokens, not hardcoded colors', async ({ page }) => {
+      await page.goto('/')
+      await page.waitForSelector('.ec', { timeout: 10000 })
+
+      // Verify a contextual token resolves to a non-empty value
+      const surfaceBg = await page.evaluate(() =>
+        getComputedStyle(document.documentElement)
+          .getPropertyValue('--c--contextuals--background--surface--primary')
+          .trim()
+      )
+      expect(surfaceBg).toBeTruthy()
+
+      // Verify the scheduler toolbar uses the token, not hardcoded white
+      const toolbarBg = await page.evaluate(() => {
+        const el = document.querySelector('.scheduler-toolbar')
+        return el ? getComputedStyle(el).backgroundColor : null
+      })
+      // Should NOT be white (#ffffff = rgb(255, 255, 255))
+      if (toolbarBg) {
+        expect(toolbarBg).not.toBe('rgb(255, 255, 255)')
+      }
+    })
+  })
 })