charlie: ESM update of auto-install

[shellscape]

Update the auto-install package to ESM following this playbook: .charlie/playbooks/upgrade-plugin-to-esm-only.md

[charliecreates]

Expand this to see my work.

• Verified packages/auto-install/src/index.ts is ESM-only (import/export default) with no require/module.exports.
• Refactored imports to node: specifiers; confirmed resolveId correctly filters installed from pkg.dependencies plus node:module builtinModules.
• Inlined RollupAutoInstallOptions in src/index.ts (with manager?: 'npm'|'yarn'|'pnpm' and test-only commands); removed legacy types/.
• Updated packages/auto-install/package.json for ESM-only: "type": "module", exports to ./dist/index.js and ./dist/index.d.ts, engines.node: >=20.19.0, peerDependencies.rollup: >=4.0.0, and scripts using tsc/vitest.
• Removed CJS-era build config by deleting rollup.config.mjs; pointed tsconfig.json at ../../.config/tsconfig.plugin.json.
• Cleaned tests: verified Vitest config (../../.config/vitest.config.mts) and ESM fixtures (test/fixtures/input.js with import 'node-noop'); removed legacy AVA tests/snapshots.
• Aligned TypeScript 5.9 workspace settings; tsc --project tsconfig.json succeeds with moduleResolution: "bundler" from the shared config.
• Built ESM artifacts: dist/index.js uses node: imports and default-exports autoInstall; dist/index.d.ts exposes RollupAutoInstallOptions and autoInstall(opts?: RollupAutoInstallOptions): Plugin.
• Ran Vitest twice via vitest --config ../../.config/vitest.config.mts run: 5 files, 6 tests passed (0 failures) with expected "installing node-noop..." stdout; noted a non-blocking TypeScript warning about missing ../../.config/tsconfig.base.json inherited by tsconfig.plugin.json.

[charliecreates]

Opened PR #1936 to migrate @rollup/plugin-auto-install to ESM-only and align it with the repo’s new pattern.

• PR: feat(auto-install)!: ESM only. Update Node and Rollup minimum versions
• Summary: switch to tsc emit (ESM-only), convert tests to Vitest, modernize Node imports, and bump minimums (Node ≥20.19.0, Rollup ≥4).

Changes

• Package metadata

  • Set "type": "module".
  • Expose ESM-only via exports: "types": "./dist/index.d.ts", "import": "./dist/index.js".
  • Bump minimums: engines.node ">=20.19.0", peerDependencies.rollup ">=4.0.0".
  • Scripts: tsc-only build (prebuild: del-cli, build: tsc --project tsconfig.json); tests run on Vitest.
  • Keep rollup as a devDependency (used in tests); add del-cli.

• TypeScript config

  • Replace package tsconfig with a symlink to .config/tsconfig.plugin.json (emits JS + d.ts to dist/).

• Source (src/index.ts)

  • Use node: specifiers and modern Node APIs.
  • Inline and export RollupAutoInstallOptions (adds 'pnpm' to manager union and a test-only commands override).

• Tests

  • Convert AVA → Vitest (test/*.test.ts), following the alias package pattern.
  • Drop brittle snapshots; assert on package.json/lockfile content and error types instead.
  • Ensure bundles are bundle.close()-d to avoid leaks.

• Cleanup

  • Remove rollup.config.mjs and the preauthored types/ folder.

Verification

# Build (tsc emit): success — dist contains index.js, index.js.map, index.d.ts, index.d.ts.map
$ pnpm -C packages/auto-install build

# Tests (Vitest): 6 passed (5 files)
$ pnpm -C packages/auto-install test

# ESLint (scoped to the package): 0 errors
$ pnpm exec eslint --cache packages/auto-install --ext .js,.ts,.mjs

This is a breaking change (CJS removed); the PR title is marked accordingly. Closes #1935.