fix(pages-router): router.push() resolves to true on success

[james-elicx]

Closes #1467

Summary

• Pages Router router.push/router.replace already resolved to true on success and false on a hard-navigation fallback via performNavigation. This PR pins down the contract on the public window.next.router surface so consumers (and the Next.js deploy test suite that awaits the return value) get a typed Promise<boolean> instead of unknown.
• Adds regression unit tests asserting await window.next.router.push("/foo") and await window.next.router.replace("/foo") resolve to true.
• Voids two router.push(...) calls in tests/e2e/app-router/build-id-navigation.spec.ts to satisfy the tightened union (App Router push is void).

Test plan

• vp test run tests/shims.test.ts -t "window.next.router.push resolves to true" (added test)
• vp test run tests/shims.test.ts (974 passed)
• vp test run tests/pages-router.test.ts (241 passed)
• vp test run tests/router-javascript-urls.test.ts (21 passed)
• vp check (no warnings or errors)

[james-elicx]

/bigbonk review

[pkg-pr-new]

Open in StackBlitz

npm i https://pkg.pr.new/vinext@1566

commit: ceda632

[github-actions]

Example	Preview	Production	Original
app-router-cloudflare	preview	production
pages-router-cloudflare	preview	production
app-router-playground	preview	production	original
realworld-api-rest	preview	production
nextra-docs-template	preview	production
benchmarks	preview	production
hackernews	preview	production	original
web	preview	production

[ask-bonk]

Clean, minimal fix. The type tightening, void annotations, and regression tests all look correct.

Verified:

• performNavigation exhaustively returns true or false on every non-throwing path (lines 916, 939, 948, 949, 960 in router.ts), so the Promise<boolean> annotation is accurate.
• push/replace in RouterMethods directly return performNavigation(...) with no intermediate processing — no path can resolve to undefined.
• The void router.push(target) in the E2E spec is the right fix: App Router push returns void, Pages Router returns Promise<boolean>, so the union is void | Promise<boolean>. void suppresses the floating-promise lint without changing behavior.
• Tests cover both push and replace via shallow navigation, which is sufficient to exercise the return-value contract without needing a full navigateClient stub.
• Test cleanup (finally block restoring window + vi.resetModules()) matches the established pattern in the surrounding window.next test block.

LGTM.

[ask-bonk]

Approved PR #1566. The change is straightforward and correct:

• The Promise<boolean> return type on PagesRouterPublicInstance.push/.replace accurately reflects what performNavigation already returns at runtime — every non-throwing path returns true or false explicitly.
• The void router.push(...) in the E2E spec is the right way to handle the void | Promise<boolean> union from the App/Pages Router type split.
• Regression tests cover both methods and use shallow navigation to isolate the return-value contract.

github run