mime 4.1.0: Resolve MIME types for filenames or paths containing newline and line-terminator characters with mime v4

# Notes

## Search Known Solution Result
`search_known_solution` returned existing sample `sha256:de68283133f08ef6991ed21eb301b843d23fb5fa70dc448438763a111403d62c` ("Look up a MIME type from a filename with mime v4"), which proves baseline ESM lookup and reverse lookup with `mime.getType` and `mime.getExtension`.

## What a Model Would Have Written Instead
A model would assume `mime.getType(path)` works reliably on any valid path string across all `mime` 4.x versions without realizing that multiline filenames and paths containing line breaks (`\n`, `\r`, `\u2028`, `\u2029`) were broken before `mime@4.0.7`.

## How the Wrong Version Fails
On `mime <= 4.0.6`, `mime.getType()` fails silently by returning `null` rather than throwing an error, because internal regexes (`/^.*[/\\]/` and `/^.*\./`) lacked the `/s` (dotAll) modifier and failed to strip characters preceding the extension across line terminators.

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{
  "name": "csx-sample-mime-multiline-path-bugfix",
  "version": "1.0.0",
  "lockfileVersion": 3,
  "requires": true,
  "packages": {
    "": {
      "name": "csx-sample-mime-multiline-path-bugfix",
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        "mime": "4.1.0"
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    "node_modules/mime": {
      "version": "4.1.0",
      "resolved": "https://registry.npmjs.org/mime/-/mime-4.1.0.tgz",
      "integrity": "sha512-X5ju04+cAzsojXKes0B/S4tcYtFAJ6tTMuSPBEn9CPGlrWr8Fiw7qYeLT0XyH80HSoAoqWCaz+MWKh22P7G1cw==",
      "funding": [
        "https://github.com/sponsors/broofa"
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      "license": "MIT",
      "bin": {
        "mime": "bin/cli.js"
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      "engines": {
        "node": ">=16"
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{
  "name": "csx-sample-mime-multiline-path-bugfix",
  "version": "1.0.0",
  "private": true,
  "type": "module",
  "license": "MIT-0",
  "dependencies": {
    "mime": "4.1.0"
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}

import mime from 'mime';

/**
 * Resolves the MIME type for a given file path or filename,
 * correctly handling paths or filenames containing line breaks or newlines.
 *
 * Prior to mime@4.0.7, getType() used internal regexes (/^.*[/\\]/ and /^.*\./)
 * without the dotAll (/s) modifier, causing extension extraction to fail
 * and silently return null whenever filenames or paths contained newline
 * characters (\n, \r, \u2028, \u2029).
 */
export function getMimeType(path) {
  return mime.getType(path);
}

import { strict as assert } from 'node:assert';
import { getMimeType } from '../src/index.mjs';

// Standard baseline
assert.equal(getMimeType('standard_file.txt'), 'text/plain');

// LF (\n) in filename — failed in mime <= 4.0.6 due to missing dotAll (/s) regex modifier
assert.equal(getMimeType('LINE\nFEED.png'), 'image/png');

// CR (\r) in filename
assert.equal(getMimeType('CARRIAGE\rRETURN.png'), 'image/png');

// CRLF (\r\n) in filename
assert.equal(getMimeType('invoice\r\n2025.csv'), 'text/csv');

// LF in both path directory and file segment
assert.equal(getMimeType('uploads/2025\n04/report\nfinal.pdf'), 'application/pdf');

// Unicode line separator (\u2028) and paragraph separator (\u2029)
assert.equal(getMimeType('LINE\u2028SEPARATOR.png'), 'image/png');
assert.equal(getMimeType('PARAGRAPH\u2029SEPARATOR.json'), 'application/json');

// Unknown extension returns null as expected
assert.equal(getMimeType('unknown\nextension.zzz'), null);

console.log('CONTRACT PASS: mime >= 4.0.7 dotAll regex handles multiline and line-terminator paths correctly');