feat: support tsx as a fallback loader for TypeScript and JSX configs (#4796)

* feat: support tsx as a fallback loader for TypeScript configs

Register `tsx/cjs` manually when the loaders known to `interpret` are
unavailable. It cannot go through `interpret`/`rechoir`: the `tsx/cjs`
entry point exists only in the package's `exports` map, which
`rechoir`'s resolver (legacy `resolve@1.x`) does not support, so it is
resolved with `createRequire` from the configuration file's location
and required directly, installing its require hook.

The loaders listed in `interpret` keep priority; `tsx` is tried only
after all of them have failed. For `.mts`, which has no `interpret`
entry at all, `tsx` is registered best-effort and the original error
reporting is preserved when it is missing. When nothing works, the
`tsx` resolution failure is appended to the existing loader failure
list before "Please install one of them".

The fixture shadows the `interpret` loaders with generated throwing
stubs (kept out of the repository — `test/**/node_modules` is already
ignored) so the tests exercise the real `tsx` package from the root
dev dependencies for both `.ts` and `.mts` configurations.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Hv8piVkEGYdWzWoWCtMcif

* feat: extend the tsx fallback loader to .jsx configurations

`tsx/cjs` also installs a require hook for `.jsx` (esbuild transform,
including `@jsx` pragma support), so offer it as a fallback there too
when the `interpret` loaders (`@babel/register`, `sucrase`) are not
installed.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Hv8piVkEGYdWzWoWCtMcif

* fix: address Copilot review feedback

- Normalize non-Error throws in the tsx registration so the
  error-reporting path can rely on `.message`.
- Fix the pre-existing "Unable load" typo ("Unable to load").
- Cover `.cts` (special-cased extension mapping) and `.tsx` (types and
  JSX together) in the fixture, alongside `.ts`, `.mts` and `.jsx`.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Hv8piVkEGYdWzWoWCtMcif

---------

Co-authored-by: Claude <noreply@anthropic.com>

Author: alexander-akait

.changeset/tsx-config-loader.md

@@ -0,0 +1,5 @@
+---
+"webpack-cli": minor
+---
+
+Support `tsx` as a fallback loader for TypeScript and JSX configuration files (`.ts`, `.tsx`, `.cts`, `.mts` and `.jsx`), used when none of the loaders known to `interpret` (such as `ts-node`) are installed.

eslint.config.mjs

@@ -16,6 +16,7 @@ export default defineConfig([
     "test/build/config-format/esm-require-await/webpack.config.js",
     "test/configtest/with-config-path/syntax-error.config.js",
     "test/build/config-format/auto/webpack.config.js",
+    "test/build/config-format/typescript-tsx/webpack.config.jsx",
   ]),
   {
     extends: [config],