feat: add font MIME types and fix dfont/ico detection collision

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

src/mime.js

@@ -1,4 +1,6 @@
 import { fileTypeFromFile } from 'file-type';
+import fs from 'node:fs/promises';
+import { probeDfont } from './converters/dfont.js';
 
 const OUTPUT_MIME_TYPES = {
   jpg: 'image/jpeg',
@@ -17,6 +19,9 @@ const OUTPUT_MIME_TYPES = {
   md: 'text/markdown',
   csv: 'text/csv',
   xlsx: 'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet',
+  ttf: 'font/ttf',
+  otf: 'font/otf',
+  woff: 'font/woff',
 };
 
 export async function detectInputMime(filePath) {
@@ -46,6 +51,13 @@ function normalizeFormat(format) {
 }
 
 export async function resolveInputFormat(filePath, declaredFormat) {
+  if (declaredFormat === 'dfont') {
+    const buffer = await fs.readFile(filePath);
+    return probeDfont(buffer)
+      ? { mime: 'application/x-dfont', valid: true }
+      : { mime: null, valid: false };
+  }
+
   const detected = await detectInputMime(filePath);
 
   if (!detected) {