feat(external): add TypeScript type definitions for external modules

Add comprehensive type definitions for external dependencies to improve type safety and IDE support:
- Add type definitions for 13 external modules (fast-glob, has-flag, normalize-package-data, npm-package-arg, pony-cause, signal-exit, spdx-correct, spdx-expression-parse, streaming-iterables, supports-color, validate-npm-package-name, which, external-pack)
- Update npm-pack.d.ts to include normalizePackageData, npmPackageArg, semver, and validateNpmPackageName
- Add pony-cause external stub for error cause chain handling
- Update build-externals config to include pony-cause

Author: jdalton

scripts/build-externals/config.mjs

@@ -26,13 +26,14 @@ export const externalPackages = [
   { name: 'debug', bundle: true },
   // pico-pack: picomatch, del, fast-glob
   { name: 'pico-pack', bundle: true },
-  // pico-pack internals - individual packages now just re-export from pico-pack bundle (no bundling needed)
   { name: 'del', bundle: false },
   { name: 'fast-glob', bundle: false },
   { name: 'fast-sort', bundle: true },
   { name: 'get-east-asian-width', bundle: true },
   { name: 'has-flag', bundle: false },
   { name: 'picomatch', bundle: false },
+  // pony-cause
+  { name: 'pony-cause', bundle: true },
   // spdx-pack: Bundle spdx-correct, spdx-expression-parse, and dependencies together.
   { name: 'spdx-pack', bundle: true },
   { name: 'spdx-correct', bundle: false },

src/external/external-pack.d.ts

@@ -0,0 +1,12 @@
+import type { default as hasFlag } from 'has-flag'
+import type { default as signalExit } from 'signal-exit'
+import type { default as supportsColor } from 'supports-color'
+
+export interface ExternalPack {
+  hasFlag: typeof hasFlag
+  signalExit: typeof signalExit
+  supportsColor: typeof supportsColor
+}
+
+declare const externalPack: ExternalPack
+export default externalPack

src/external/fast-glob.d.ts

@@ -0,0 +1,8 @@
+import type { PicoPack } from './pico-pack'
+
+export type FastGlob = PicoPack['glob']
+
+declare const fastGlob: FastGlob
+export default fastGlob
+
+export const { glob, globStream, globSync } = fastGlob

src/external/has-flag.d.ts

@@ -0,0 +1 @@
+export { hasFlag as default } from './external-pack'

src/external/normalize-package-data.d.ts

@@ -0,0 +1,4 @@
+import type { NpmPack } from './npm-pack'
+
+declare const normalizePackageData: NpmPack['normalizePackageData']
+export default normalizePackageData

src/external/npm-pack.d.ts

@@ -3,13 +3,21 @@ import type libnpmpack from 'libnpmpack'
 import type * as cacache from 'cacache'
 import type makeFetchHappen from 'make-fetch-happen'
 import type Arborist from '@npmcli/arborist'
+import type normalizePackageData from 'normalize-package-data'
+import type npmPackageArg from 'npm-package-arg'
+import type * as semver from 'semver'
+import type validateNpmPackageName from 'validate-npm-package-name'
 
 export interface NpmPack {
   Arborist: typeof Arborist
   pacote: Pick<typeof pacote, 'extract'>
   libnpmpack: typeof libnpmpack
   cacache: Pick<typeof cacache, 'get' | 'put' | 'rm' | 'ls' | 'tmp'>
   makeFetchHappen: Pick<typeof makeFetchHappen, 'defaults'>
+  normalizePackageData: typeof normalizePackageData
+  npmPackageArg: typeof npmPackageArg
+  semver: typeof semver
+  validateNpmPackageName: typeof validateNpmPackageName
 }
 
 declare const npmPack: NpmPack

src/external/npm-package-arg.d.ts

@@ -0,0 +1,4 @@
+import type { NpmPack } from './npm-pack'
+
+declare const npmPackageArg: NpmPack['npmPackageArg']
+export default npmPackageArg

src/external/pony-cause.d.ts

@@ -0,0 +1,14 @@
+export class ErrorWithCause extends Error {
+  constructor(message: string, options?: { cause?: unknown })
+}
+
+export function findCauseByReference(
+  error: Error,
+  reference: Error,
+): Error | undefined
+
+export function getErrorCause(error: Error): Error | undefined
+
+export function stackWithCauses(error: Error): string
+
+export function messageWithCauses(error: Error): string

src/external/pony-cause.js

@@ -0,0 +1,3 @@
+'use strict'
+
+module.exports = require('pony-cause')

src/external/signal-exit.d.ts

@@ -0,0 +1 @@
+export { signalExit as default } from './external-pack'