* fix(native): report unidentified text plists as unknown
Require explicit XML identification in file output instead of treating all
text as XML. Preserve decoded plist values and source-format provenance
when plutil falls back to XML conversion.
Add provider-boundary regressions and real macOS CLI controls for OpenStep,
data-bearing OpenStep, XML, UTF-16 XML and binary property lists.
Fixes#4294
* fix(native): keep XML plists without a declaration labeled xml
`file -b` names XML only when a document declaration is present, so the
narrowed `\bXML\b` check reported a declaration-less XML plist as unknown and
broke the real-plutil `decodes xml plists that plutil cannot express as JSON`
CLI test. When `file` reports only text, read the source head once and label it
XML only when its first non-whitespace character (after a UTF-8 BOM) is `<`;
OpenStep and other text stay unknown.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
* fix(native): distinguish OpenStep data from XML source markup
Recognize XML markup instead of treating every leading angle bracket as XML.
Keep data-only OpenStep sources unknown, honor explicit JSON identification,
and decode BOM-marked UTF-16 prefixes before detecting declarationless XML.
Add source-format regressions and macOS CLI cases for data-only sources.
---------
Co-authored-by: Kaoru0822 <208281322+kaoru0822-kitauji@users.noreply.github.com>
Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>
