fix(plist): own dictionary decoding across Apple workflows

Preserve XML, OpenStep and binary dictionary keys at their format owners. Share validated binary reference facts with materialization while retaining scalar precision, UID identity and bounded expansion. Migrate archive, Interface Builder, native and app-bundle consumers, then remove obsolete key-omission accounting and schema copies.

Validated source regressions and compiled CLI/MCP workflows, including native plist fidelity and archive identity. Typecheck, lint, docs and test discovery pass. No performance benchmarks were required.

docs/native-investigation.md

@@ -641,11 +641,10 @@ complete observation.
   outcome instead of rounded reference identities.
   UID 0 cannot distinguish conditional nil from ordinary nil. Limits are
   64 MiB of input, 200,000 objects/references and 128 nesting levels.
-  XML dictionary entries decoded as `__proto__` are omitted with an explicit
-  count because REA results cannot represent that key. XML tag whitespace and
-  comments do not change that handling. XML key names combine their text and
-  CDATA segments without trimming or expanding literal CDATA entities. Other
-  values and the original archive digest are preserved.
+  XML, OpenStep and binary dictionary entries retain their source keys,
+  including `__proto__`, through archive projection and CLI/MCP results.
+  XML key names combine their text and CDATA segments without trimming or
+  expanding literal CDATA entities. The original archive digest is preserved.
   Symbol fallback accepts complete Objective-C class/metaclass symbol leaves,
   including qualified names. Pointer/string labels that merely contain a class
   marker do not establish classes. Provider namespace method labels are not