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

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

test/mime.test.js

@@ -104,3 +104,35 @@ describe('resolveInputFormat — heic/heif alias', () => {
     expect(result.valid).toBe(true);
   });
 });
+
+describe('outputMimeType — fonts', () => {
+  it('returns the correct MIME type for each font target format', () => {
+    expect(outputMimeType('ttf')).toBe('font/ttf');
+    expect(outputMimeType('otf')).toBe('font/otf');
+    expect(outputMimeType('woff')).toBe('font/woff');
+  });
+});
+
+describe('resolveInputFormat — dfont', () => {
+  it('confirms file-type alone misidentifies the dfont fixture as ico (documents the bug this fix works around)', async () => {
+    const fixturePath = path.join(import.meta.dirname, 'fixtures', 'sample.dfont');
+    const detected = await detectInputMime(fixturePath);
+    expect(detected.ext).toBe('ico');
+  });
+
+  it('accepts a real dfont file despite that misidentification', async () => {
+    const fixturePath = path.join(import.meta.dirname, 'fixtures', 'sample.dfont');
+    const result = await resolveInputFormat(fixturePath, 'dfont');
+    expect(result).toEqual({ mime: 'application/x-dfont', valid: true });
+  });
+
+  it('rejects content starting with the colliding magic bytes that is not a real dfont', async () => {
+    const fixturePath = path.join(import.meta.dirname, 'fixtures', 'sample-fake.dfont');
+    await fs.writeFile(fixturePath, Buffer.from([0x00, 0x00, 0x01, 0x00, 0x01, 0x00, 0x10, 0x10]));
+
+    const result = await resolveInputFormat(fixturePath, 'dfont');
+    expect(result).toEqual({ mime: null, valid: false });
+
+    await fs.unlink(fixturePath);
+  });
+});