test(web): align jsdom abort signals with Node

apps/web/src/test/setup.spec.ts

@@ -0,0 +1,14 @@
+import { describe, expect, it } from 'vitest';
+
+describe('Vitest abort-controller realm', () => {
+  it('provides a global signal accepted by Node native Request', () => {
+    const controller = new AbortController();
+    const request = new Request('https://mosaic.invalid/navigation', {
+      signal: controller.signal,
+    });
+
+    expect(request.signal).toBeInstanceOf(AbortSignal);
+    controller.abort();
+    expect(request.signal.aborted).toBe(true);
+  });
+});

apps/web/src/test/setup.ts

@@ -0,0 +1,23 @@
+import { transferableAbortController } from 'node:util';
+
+// jsdom installs realm-local abort constructors while Node's undici Request
+// remains native. React Router passes a global AbortSignal to Request, so both
+// constructors must come from Node's native realm during tests.
+const nativeController = transferableAbortController();
+const nativeAbortController = nativeController.constructor;
+const nativeAbortSignal = nativeController.signal.constructor;
+
+for (const target of [globalThis, window]) {
+  Object.defineProperties(target, {
+    AbortController: {
+      configurable: true,
+      writable: true,
+      value: nativeAbortController,
+    },
+    AbortSignal: {
+      configurable: true,
+      writable: true,
+      value: nativeAbortSignal,
+    },
+  });
+}

apps/web/vitest.config.ts

@@ -14,6 +14,8 @@ export default defineConfig({
   test: {
     globals: true,
     environment: 'jsdom',
+    setupFiles: ['./src/test/setup.ts'],
+    isolate: true,
     exclude: ['e2e/**', 'node_modules/**'],
   },
 });

docs/scratchpads/webui-p2-data-auth.md

@@ -110,3 +110,53 @@ Run fresh after remediation from the locations required by the brief:
 
 - `.mosaic/orchestrator/session.lock` is modified by the active harness and must remain unstaged.
 - P2 changes shared `src/lib/` modules consumed by both Vite and Next, so the Next build is a required compatibility gate.
+
+## Remediation 1 — independent Node 26 verification failure
+
+**Correction received:** 2026-08-09
+
+The orchestrator rejected the P2 verification claim after an independent run under Node 26.4.0 produced 2 failed redirect tests and 2 unhandled errors. React Router passed jsdom's realm-local `AbortSignal` to Node 26's native undici `Request`, which rejects non-native signals. Production guard behavior is correct and must not change.
+
+### Remediation constraints
+
+- Preserve both redirect assertions and all `guards.tsx` behavior; no skips, weakening, or test deletion.
+- Add the smallest Vitest environment repair so global `AbortController` / `AbortSignal` are constructors accepted by native undici `Request`.
+- Run all six required gates, commit named files locally without pushing, leave `.mosaic/orchestrator/session.lock` untouched, then run `apps/web: pnpm test` as the final worktree action.
+- Completion requires zero failed tests, zero test errors, and zero unhandled rejections.
+
+### Remediation plan
+
+1. Reproduce under Node 26.4.0 if an ephemeral matching runtime is available.
+2. Add a Vitest `setupFiles` module deriving Node-native abort constructors from `node:util` and register it in `apps/web/vitest.config.ts`.
+3. Add a direct regression assertion that a global controller's signal is accepted by native `Request`, while retaining the existing redirect behavior tests unchanged.
+4. Run focused Node 22 and Node 26 tests, independent review, all required gates, and local commit(s).
+5. After every edit/commit/status check is complete, run `pnpm test` from `apps/web` as the last command.
+
+### Remediation implementation and evidence
+
+- Reproduced under ephemeral Node `v26.4.0`: `Test Files 1 failed (1)`, `Tests 2 failed | 4 passed (6)`, `Errors 2 errors`, with the exact undici `AbortSignal` realm rejection from the remediation brief.
+- Added `apps/web/src/test/setup.ts`, registered through `vitest.config.ts#setupFiles`. It derives Node-native abort constructors from the built-in `node:util.transferableAbortController()` and aligns both `globalThis` and jsdom `window`; it does not replace `Request`, `Response`, or `fetch`.
+- Explicitly pinned Vitest `isolate: true` so the test-only global constructors cannot leak between test-file environments.
+- Added `src/test/setup.spec.ts`, which proves a global controller signal is accepted by Node's native `Request` and that abort propagation remains functional.
+- Existing `guards.spec.tsx` and production `guards.tsx` remain unchanged.
+- Focused Node 26.4.0 remediation run: `Test Files 2 passed (2)` and `Tests 7 passed (7)`, with zero errors/unhandled rejections.
+- Preliminary full Node 26.4.0 run: `Test Files 9 passed (9)` and `Tests 27 passed (27)`, with zero errors/unhandled rejections before the direct setup regression was added.
+- No dependency was added; `node:util` is a Node built-in.
+
+### Remediation independent review
+
+- First code review: approve, 0 blockers, 0 should-fix; suggested a direct Request regression and version-neutral comment.
+- First security/integrity review: low risk; suggested pinning test isolation explicitly.
+- All suggestions were applied.
+- Fresh code re-review: approve, 0 blockers, 0 should-fix, no findings.
+- Fresh security/integrity re-review: low risk, 0 findings.
+
+### Remediation pre-commit gate evidence
+
+- Node 26.4.0 `pnpm test`: `Test Files 10 passed (10)`; `Tests 28 passed (28)`; zero errors and zero unhandled rejections.
+- `pnpm typecheck`: `tsc --noEmit` exited 0.
+- `pnpm build:vite`: `✓ 113 modules transformed`; `✓ built in 960ms`.
+- `pnpm build` (Next): `✓ Compiled successfully in 4.8s`; static pages generated 10/10.
+- `pnpm lint`: `eslint src` exited 0.
+- Root `pnpm format:check`: `All matched files use Prettier code style!`.
+- Final post-commit non-test gates and final-action Node 26 `pnpm test` remain required before reporting completion.