fix(layout): avoid blank column-mode workspace on special tabs

apps/desktop/src/components/layout/__tests__/tabWorkspaceLayout.column-mode-special-pages.spec.ts

@@ -0,0 +1,41 @@
+import { readFileSync } from "node:fs";
+import { describe, expect, it } from "vitest";
+
+const appSource = readFileSync(new URL("../../../App.vue", import.meta.url), "utf8");
+const tabBarSource = readFileSync(new URL("../AppTabBar.vue", import.meta.url), "utf8");
+
+function sourceBetween(source: string, start: string, end: string): string {
+  const startIndex = source.indexOf(start);
+  const endIndex = source.indexOf(end, startIndex + start.length);
+  expect(startIndex).toBeGreaterThanOrEqual(0);
+  expect(endIndex).toBeGreaterThan(startIndex);
+  return source.slice(startIndex, endIndex);
+}
+
+// Regression test for #8213: AppTabBar's settings/driver special-page strip is
+// still a horizontal-only "w-full" bar. Placing it inside a flex-row /
+// flex-row-reverse workspace (left/right column tab placement) squeezes the
+// sibling content pane (EditorSettingsPage/DriverStorePage) to zero width,
+// making the settings/driver page invisible after it's reopened. The fix
+// falls back to a flex-col workspace while either special page is active.
+describe("tabWorkspaceLayoutClass column-mode special-page fallback", () => {
+  const computedBlock = sourceBetween(appSource, "const tabWorkspaceLayoutClass = computed(() => {", "});");
+
+  it("falls back to flex-col while the settings/driver strip is active, before the vertical branch", () => {
+    const specialPageGuardIndex = computedBlock.indexOf("isSpecialPageStripActive.value");
+    const verticalRowIndex = computedBlock.indexOf('isVerticalTabPlacement.value ? "flex-row" : "flex-col"');
+    expect(specialPageGuardIndex).toBeGreaterThanOrEqual(0);
+    expect(verticalRowIndex).toBeGreaterThan(specialPageGuardIndex);
+    expect(computedBlock).toMatch(/isVerticalTabPlacement\.value\s*&&\s*isSpecialPageStripActive\.value\)\s*return\s*"flex-col"/);
+  });
+
+  it("derives isSpecialPageStripActive from the same flags AppTabBar uses to render", () => {
+    expect(appSource).toContain("const isSpecialPageStripActive = computed(() => driverStoreActive.value || settingsStore.settingsPageActive);");
+    // AppTabBar itself only renders while one of these is true - keep the guard in sync with it.
+    expect(tabBarSource).toContain('v-if="driverStoreActive || settingsPageActive"');
+  });
+
+  it("still stretches the special-page strip full width (the part the flex-col fallback protects against)", () => {
+    expect(tabBarSource).toMatch(/class="app-tab-bar[^"]*\bw-full\b/);
+  });
+});