Handle OPF metadata comments and record Highest Exam edition QA

tests/test_edition.py

@@ -182,3 +182,19 @@ def test_new_edition_uuid_keeps_obfuscated_font_readable_and_audited(tmp_path):
     with zipfile.ZipFile(out) as z,zipfile.ZipFile(damaged,'w') as target:
         for info in z.infolist(): target.writestr(info,b'broken' if info.filename==active else z.read(info.filename))
     assert any('font_binding' in issue for issue in audit_edition(damaged)['issues'])
+
+
+def test_metadata_comments_survive_localization(tmp_path):
+    source,cfg,image,review,_ = fixture(tmp_path)
+    commented=tmp_path/'commented.epub'
+    with zipfile.ZipFile(source) as z,zipfile.ZipFile(commented,'w') as target:
+        for info in z.infolist():
+            raw=z.read(info.filename)
+            if info.filename=='EPUB/package.opf':
+                raw=raw.replace(b'<metadata>',b'<metadata><!-- Publisher metadata comment -->')
+            target.writestr(info,raw)
+    out=tmp_path/'localized.epub'
+    localize(commented,out,cfg,'target_only',image,review)
+    assert audit_edition(out)['issues']==[]
+    with zipfile.ZipFile(out) as z:
+        assert b'<!-- Publisher metadata comment -->' in z.read('EPUB/package.opf')