Implement fs-extra as a built-in package; hoist lazily defined error classes

.gitignore

@@ -51,3 +51,6 @@ tmp-*/
 .env.local
 .env*
 .env*.local
+# the vendored fs-extra corpus package: its lib/output module and jsonfile's own universalify
+!tests/corpus/fs-extra-package/node_modules/fs-extra/lib/output/
+!tests/corpus/fs-extra-package/node_modules/jsonfile/node_modules/

docs/content/docs/dependencies.mdx

@@ -71,7 +71,7 @@ Some packages your program imports directly ship no declarations, so their types
 $ scriptc build app.ts --npm-static=three -o app >/dev/null
 ```
 
-Naming a package skips the declaration requirement above, but the package still has to compile. Add a trailing `...` to select a package together with every package it depends on, for example `--npm-static=fs-extra...`. `--npm-static=auto` uses the default automatic selection. The option accepts a comma-separated list and can be repeated.
+Naming a package skips the declaration requirement above, but the package still has to compile. Add a trailing `...` to select a package together with every package it depends on, for example `--npm-static=semver...`. `--npm-static=auto` uses the default automatic selection. The option accepts a comma-separated list and can be repeated.
 
 ## Built-in packages
 
@@ -84,6 +84,12 @@ scriptc implements a few packages itself and compiles that implementation in pla
 - `fetch` with a dispatcher returns a response whose `url` is empty and whose `redirected` is `false`, offers only `gzip, deflate` encodings, and sends string and byte bodies. Without a dispatcher it is the built-in `fetch`.
 - Request bodies are strings and bytes; stream, iterable and form-data bodies, `pipelining` above 1, `CONNECT` requests and Unix socket paths aren't supported.
 
+`fs-extra` 8.x through 11.x is built in, and its declarations replace `@types/fs-extra`. The default import, a namespace import and named imports all read the same exports. fs's members are re-exported, and fs-extra's wrapped methods follow its rule: with a callback as the last argument they call back, otherwise they return a promise. The extra methods cover `copy`, `copySync`, `move`, `moveSync`, `remove`, `removeSync`, `emptyDir`, `ensureDir`, `mkdirs`, `mkdirp`, `ensureFile`, `pathExists`, `outputFile`, `readJson`, `readJsonSync`, `writeJson`, `writeJsonSync`, `outputJson` and their aliases, with fs-extra's error messages. Known differences:
+
+- `ensureLink`, `ensureSymlink`, `createLink`, `createSymlink`, `gracefulify`, the promise forms of the descriptor-based methods, and the callback forms of `stat`, `lstat`, `readdir`, `mkdtemp`, `realpath` and `readJson` aren't declared, so using one is a type error at build time. Paths are strings, text is UTF-8, and write flags, string modes and `copyFile` mode flags aren't accepted.
+- graceful-fs's retry queue, which fs-extra uses under Node.js, isn't part of the implementation, so a program that runs out of file descriptors fails at the first `EMFILE` error instead of retrying.
+- An ES module that imports fs-extra can use any of its exports by name. Node.js only exposes the names its CommonJS lexer finds in fs-extra's source, so a name like `readFile` throws a `SyntaxError` there.
+
 Small polyfill packages whose module is exactly a Node.js built-in on Node.js 24 compile as that built-in, at the `require()` that loads them, from your program's CommonJS files, from compiled packages, and from esbuild bundles whose module paths name the package and its version (as pnpm installs do). The package's own files aren't compiled.
 
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