feat(javascript): report observed export property presence (#1160)

* feat(javascript): report observed export property presence

Extend compare_javascript_export_shapes so each retained return variant
lists observed property names and each change reports presence independently
of value resolution. Complete parent coverage classifies one-sided names as
added or removed even when static values stay unknown.

Fixes #725

* test(javascript): match unknown export-shape values by availability

Nested availability objects include a reason when values stay unresolved.
Assert availability through objectContaining so presence-only added and
removed rows still verify unknown values.

* fix(javascript): preserve uncertain export property presence and locations

* fix(javascript): normalize presence and preserve local property coverage

* fix(javascript): require present discriminants for return pairing

* fix(javascript): normalize retained shapes before comparison

* refactor(javascript): share return projection with executable examples

* fix(javascript): localize uncertainty for missing mutated slots

* fix(javascript): bind advertised export examples to exact artifacts

* fix(javascript): keep uncertain property flow as candidates

---------

Co-authored-by: morluto <76467478+morluto@users.noreply.github.com>

src/application/javascript/JavaScriptSemanticGraphValueProjection.ts

@@ -69,7 +69,10 @@ const projectValue = (input: ValueProjectionInput): void => {
         source: target,
         target: slot,
         relation: "writes-property",
-        resolution: value.unknownProperties ? "candidate" : "resolved",
+        resolution:
+          value.unknownProperties || property.presence === "unknown-coverage"
+            ? "candidate"
+            : "resolved",
       });
       projectValue({
         context,