fix(tests): three more portal query-root failures (pr-tab, worktree-terminal, milestone-slice) (#2959)

Three dashboard test files asserted against `render()`'s `container`,
but the components under test mount through `createPortal` — so
`container` is **empty** and every query returns nothing. Same root
cause as the earlier portal batch; these are the three that were still
held back.

| File | Before | After |
|---|---|---|
| `TaskDetailModal.pr-tab` | failing | pass |
| `TaskDetailModal.worktree-terminal` | failing | pass |
| `MilestoneSliceInterviewModal` | failing | pass |

**Measured: 39/39 passing**, rebased on current main (`3461ae7a92`).
Lint clean, FNXC date gate exit 0.

### Why this stayed hidden

The queries were a **mix** of `container.querySelector(...)` and
`screen.*`. `screen` queries `document`, so they kept working — a
portal-mounted modal makes only the `container` half go blind. The
result is a file that looks half-alive rather than obviously broken, and
the failures present as five different-looking symptoms (`null`,
`undefined`, `+0`, `[]`, `-1`) that don't read as one bug.

Grouping candidate files by **`container.querySelector` call count**
rather than by symptom is what identified these correctly, and — the
part that mattered — correctly *excluded* the neighbouring files that
were failing for unrelated reasons.

### One thing to know if you repeat this

A blanket `container` → `document` replace is wrong: it also rewrites
`renderResult.container.querySelector` into
`renderResult.document.querySelector`, which is not a thing. That broke
two already-passing tests on my first attempt. This uses two separate
passes with a lookbehind so only the bare receiver is rewritten.

### Scope

Test-side only — **no product code changes**, so no changeset. This does
not fix the *cause* (tests are still free to query the wrong root); a
lint rule for that is worth considering separately, but it would need to
distinguish portal-mounting components from ordinary ones, and I did not
want to guess at that boundary inside a test-fix PR.

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

* **Tests**
* Improved modal and task detail accessibility test reliability by
querying rendered elements from the document.
* Updated coverage for keyboard navigation, Pull Request status
indicators, tab ordering, and onboarding provider cards.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

---------

Co-authored-by: Claude Opus 5 (1M context) <noreply@anthropic.com>

packages/dashboard/app/components/__tests__/MilestoneSliceInterviewModal.test.tsx

@@ -272,7 +272,7 @@ describe("MilestoneSliceInterviewModal", () => {
         targetTitle="Milestone 1"
       />,
     );
-    const modal = container.querySelector(".planning-modal");
+    const modal = document.querySelector(".planning-modal");
 
     expect(mockUseMobileKeyboard).toHaveBeenCalledWith({ enabled: true });
     expect(modal?.getAttribute("style")).toContain("--keyboard-overlap: 250px");

packages/dashboard/app/components/__tests__/TaskDetailModal.pr-tab.test.tsx

@@ -72,11 +72,11 @@ describe("TaskDetailModal Pull Request tab", () => {
     );
 
     expect(screen.queryByTestId("pr-panel-stub")).toBeNull();
-    expect(container.querySelector(".detail-in-review-stall")).toBeNull();
+    expect(document.querySelector(".detail-in-review-stall")).toBeNull();
 
     fireEvent.click(screen.getByRole("button", { name: "Pull Request" }));
 
     expect(screen.getByTestId("pr-panel-stub")).toBeInTheDocument();
-    expect(container.querySelector(".detail-in-review-stall")).toBeTruthy();
+    expect(document.querySelector(".detail-in-review-stall")).toBeTruthy();
   });
 });

packages/dashboard/app/components/__tests__/TaskDetailModal.worktree-terminal.test.tsx

@@ -165,7 +165,7 @@ describe("TaskDetailModal worktree terminal tab", () => {
     const { container } = renderDetail();
 
     await screen.findByRole("button", { name: "Terminal" });
-    const tabLabels = Array.from(container.querySelectorAll<HTMLButtonElement>(".detail-tabs .detail-tab"))
+    const tabLabels = Array.from(document.querySelectorAll<HTMLButtonElement>(".detail-tabs .detail-tab"))
       .map((tab) => tab.textContent?.trim());
 
     expect(tabLabels.indexOf("Comments")).toBeGreaterThanOrEqual(0);

packages/dashboard/app/components/__tests__/onboarding-flow.test.tsx

@@ -522,7 +522,7 @@ describe("onboarding flow integration", () => {
         ],
       });
 
-      const { container } = renderModal();
+      renderModal();
 
       await waitFor(() => {
         expect(screen.getByTestId("onboarding-apikey-input-anthropic-api-key")).toBeInTheDocument();
@@ -530,7 +530,14 @@ describe("onboarding flow integration", () => {
 
       const subscriptionCard = screen.getByTestId("onboarding-provider-card-anthropic-subscription");
       const anthropicCard = screen.getByTestId("onboarding-provider-card-anthropic-api-key");
-      const renderedAnthropicAuthCards = container.querySelectorAll(
+      /*
+      FNXC:OnboardingTests 2026-07-30-15:10:
+      `document`, not `render()`'s `container` — the onboarding modal mounts through a portal, so
+      `container` is empty and this counted 0 cards while the `screen.getByTestId` calls two lines
+      up found both. That split is what made this failure read as an onboarding-provider bug rather
+      than a query-root bug.
+      */
+      const renderedAnthropicAuthCards = document.querySelectorAll(
         '[data-testid^="onboarding-provider-card-anthropic"]',
       );
       expect(renderedAnthropicAuthCards).toHaveLength(2);

scripts/lib/fnxc-future-dates-baseline.json

@@ -180,7 +180,6 @@
   "packages/engine/src/__tests__/review-handoff-lane.test.ts": 1,
   "packages/engine/src/__tests__/scheduler-fanout-escalation-lanes.test.ts": 2,
   "packages/engine/src/__tests__/scheduler-load-lane-union.test.ts": 2,
-  "packages/engine/src/__tests__/scheduler-paused-dispatch-refusal.test.ts": 3,
   "packages/engine/src/__tests__/self-blocked-dependency-deadlock.pg.test.ts": 1,
   "packages/engine/src/__tests__/self-healing-db-corruption.test.ts": 1,
   "packages/engine/src/__tests__/stale-task-reporter.test.ts": 1,