next.js

a249dcbc - (TypeScript 7 Support) Add experimental TypeScript CLI backend (#95639)

(TypeScript 7 Support) Add experimental TypeScript CLI backend (#95639) ## Summary - add `experimental.useTypeScriptCli` so projects can explicitly run their local `tsc` during `next build`, including TypeScript 7 while the legacy JavaScript API is unavailable - preserve the TypeScript API backend as the default, with TypeScript 6-compatible dependency installation and actionable TypeScript 7 migration guidance - load effective compiler metadata through `tsc --showConfig`, preserve inherited path origins, stream native diagnostics, redirect incremental state, and forward worker termination to the compiler process tree - document the experimental behavior and cover TypeScript 6/7, both bundlers, raw diagnostics, full-project checking, dependency selection, and cleanup ## Demo ``` pnpm build > cna@0.1.0 build /Users/timneutkens/projects/sandbox/cna > next build ▲ Next.js 16.3.0-canary.81 (Turbopack) ✓ Running next.config.ts took 23ms - Cache Components enabled - Experiments (use with caution): ✓ useTypeScriptCli Creating an optimized production build ... ✓ Compiled successfully in 3.9s Running TypeScript ... app/page.tsx:8:3 - error TS2322: Type 'string' is not assignable to type 'number'. 8 return count++ + "abc"; ~~~~~~ Found 1 error in app/page.tsx:8 Failed to type check. Next.js build worker exited with code: 1 and signal: null  ELIFECYCLE  Command failed with exit code 1. ``` ## Verification - `pnpm test-start-turbo test/production/app-dir/typescript-cli/typescript-cli.test.ts` - `pnpm test-start-webpack test/production/app-dir/typescript-cli/typescript-cli.test.ts` - `pnpm test-start-turbo test/production/ci-missing-typescript-deps/index.test.ts` - `pnpm test-dev-turbo test/development/typescript-native-preview/index.test.ts` - `pnpm test-start-turbo test/production/typescript-basic/index.test.ts` <!-- NEXT_JS_LLM_PR -->