feat(ui): add decorative style primitives

src/lib/ui/storybook.test.ts

@@ -12,6 +12,8 @@ const requiredStoryFiles = [
   "DashboardFrame.stories.svelte",
   "DashboardHeader.stories.svelte",
   "DashboardOnePager.stories.svelte",
+  "CornerBracketFrame.stories.svelte",
+  "DiagonalStripeField.stories.svelte",
   "FooterCell.stories.svelte",
   "FooterStatusCell.stories.svelte",
   "GridFrame.stories.svelte",
@@ -24,10 +26,12 @@ const requiredStoryFiles = [
   "ServiceGroupPanel.stories.svelte",
   "ServicePanel.stories.svelte",
   "ServiceRow.stories.svelte",
+  "SignalTrace.stories.svelte",
   "Sparkline.stories.svelte",
   "StatusBadge.stories.svelte",
   "StatusStrip.stories.svelte",
   "SystemState.stories.svelte",
+  "ScanlineField.stories.svelte",
   "TelemetryCard.stories.svelte",
   "TelemetryGrid.stories.svelte",
   "TelemetryStrip.stories.svelte",
@@ -79,6 +83,36 @@ describe("Storybook inventory", () => {
     }
   });
 
+  test("includes style-only decorative primitives in the reusable UI inventory", () => {
+    for (const component of [
+      "CornerBracketFrame",
+      "DiagonalStripeField",
+      "ScanlineField",
+      "SignalTrace",
+    ]) {
+      expect(existsSync(join(componentsDir, `${component}.svelte`)), `${component} is missing`).toBe(
+        true,
+      );
+      expect(
+        existsSync(join(storiesDir, `${component}.stories.svelte`)),
+        `${component}.stories.svelte is missing`,
+      ).toBe(true);
+    }
+  });
+
+  test("keeps decorative primitives hidden from assistive technology", () => {
+    for (const component of [
+      "CornerBracketFrame",
+      "DiagonalStripeField",
+      "ScanlineField",
+      "SignalTrace",
+    ]) {
+      const source = readFileSync(join(componentsDir, `${component}.svelte`), "utf8");
+
+      expect(source).toContain('aria-hidden="true"');
+    }
+  });
+
   test("does not add deferred form/navigation primitives", () => {
     for (const component of ["Input", "ToggleGroup", "ScrollArea"]) {
       expect(existsSync(join(root, `src/lib/ui/components/${component}.svelte`))).toBe(false);