feat(screens): Next.js as a Screens app — pages, route handlers, links and redirects

- frameworks/nextjs.ts (split out of react.ts): App Router app/**/page.tsx and Pages Router pages → routes named by path ((group) stripped, [slug] → :slug, [...all] → :all*), bound to the default export; app/**/route.ts exports → METHOD /api/… endpoints referencing their functions; pages/api → ANY; resolve() claims router.push/replace/prefetch, redirect/permanentRedirect and NextResponse.redirect(new URL(…)) into navigates edges via the Expo href readers, against a Next-only route table gated on the app's root
- next-router-synthesizer.ts: <Link href> and internal <a href> → dashed navigates edges from the component (next-link, registeredAt)
- expo-router.ts: href readers exported; matcher accepts :param / :all* segments
- steps.ts: a Next page's own work fires from page load; a Next page makes the project a web app; {status: 201} read off the call site (branch-guards CallSiteText.status) for response rows
- frameworks/package-deps.ts: nested package.json files probed on disk (getAllFiles lists only sources); Express/React/Expo/Nest detectors use it; routing manifest names constant handlers
- tests: nextjs.test.ts (file→route rules, extract, verbs, end to end with Screens and Steps); frameworks.test.ts Next cases moved to the Next resolver
- docs: CHANGELOG, spec §3.12 frameworks paragraph, CLAUDE.md, synthesis doc, plan P4 built, playbook rows for Next / MERN / Nest channels

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01REFyW9hmNrxhwN5wxRoAkC

docs/design/dynamic-dispatch-coverage-playbook.md

@@ -277,6 +277,9 @@ Status legend: ✅ done+validated · 🔬 hole identified · ⬜ not started.
 
 (Verify the exact supported set against `src/extraction/languages/` and
 `src/resolution/frameworks/` before starting — this table is a starting point.)
+| TypeScript/JS | Next.js (App Router + Pages Router) | page → `<Link>` / `router.push` / `redirect` → page; page load → data; client component → `'use server'` action → DB → `redirect`; `route.ts` handler → DB → response | R + S | ✅ 2026-08-28 (`frameworks/nextjs.ts`, `next-router-synthesizer.ts`, Steps `load` trigger + server-action crossing): fixture `__tests__/nextjs.test.ts` end to end (Screens `routed`, the push attributed back under its condition, the action's redirect); `leerob/next-saas-starter` indexes its pages and links. 🔬 agent A/B (`--model sonnet`, ≥2 runs/arm) not run yet |
+| TypeScript/JS | Express + React (MERN monorepo) | client `axios` / `fetch` literal path → own route → handler → Mongoose → response rows | S + R | ✅ 2026-08-28 (`tier-synthesizer.ts` `http-client` + Express mounts / chained `router.route()` / wrapped `const h = asyncHandler(…)` handlers / nested `package.json` detection): `bradtraversy/proshop_mern` 49 routes (19 pages + 30 endpoints), 23 client→route edges, every one spot-checked correct; `login → ⇢ POST /api/users/login → User.findOne → 401 rows → jwt.sign`. Node count stable across re-index. 🔬 A/B not run |
+| TypeScript/JS | NestJS queues / events / sockets | `queue.add('job')` → `@Process('job')`; `emit('x')` → `@OnEvent('x')`; `socket.emit` → `@SubscribeMessage` and `server.emit` → `socket.on` | S | ✅ 2026-08-28 (`tier-synthesizer.ts` `queue-job`, `event-bus`): `nestjs/nest` `sample/26-queues` (`transcode` → `handleTranscode`) and `sample/30-event-emitter` (`order.created` → its listener) exact, 0 wrong edges after the `e2e/` and generic-event guards; `immich-app/immich` 0 edges — a generated SDK client and a wrapped queue API carry no literal, so silence (correct). 🔬 A/B not run |
 
 ### Retrieval A/Bs that are not coverage work