Fix fallback route params case in app-page handler (#91737)
## Summary
- add production-route-shape fixture coverage for
`/[teamSlug]/[project]/settings/domains`
- add revalidation helpers (API and server action) and browser controls
used by the regression test
- reproduce the failing production sequence by priming, revalidating,
then loading a page with in-view `next/link` and navigating repeatedly
x-ref: https://github.com/vercel/next.js/pull/91627
x-ref: https://github.com/vercel/next.js/pull/91603
## Testing
- `IS_WEBPACK_TEST=1 NEXT_SKIP_ISOLATE=1 NEXT_TEST_MODE=start pnpm
testheadless
test/e2e/app-dir/segment-cache/vary-params-base-dynamic/vary-params-base-dynamic.test.ts
-t "production route shape"` (passes)
- `NEXT_ENABLE_ADAPTER=1 pnpm test-deploy
test/e2e/app-dir/segment-cache/vary-params-base-dynamic/vary-params-base-dynamic.test.ts
-t "production route shape"`
- `NEXT_ENABLE_ADAPTER=1 pnpm test-deploy
test/e2e/app-dir/segment-cache/vary-params-base-dynamic/vary-params-base-dynamic.test.ts`
(fails in the two production-shape cases)
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Co-authored-by: Zack Tanner <1939140+ztanner@users.noreply.github.com>
