fix(javascript): keep exact empty values in graph identities

#839 displayed empty artifact-local keys and source-map original names as
`""` inside node identities, so `fetch("")` and `fetch('""')` (or
`sources: ["", "\"\""]`) produced the same node ID and merged two
distinct facts. Function nodes likewise exposed only a display label, so
`['']()` and `['""']()` were indistinguishable.

Admit the exact empty string in `artifact-local-key.key` and
`source-map-original.original_source`, keep the `""` substitution for
labels only, and record each function node's exact `name` in its
properties. Regenerate the catalog digests for the relaxed output schema.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/application/JavaScriptSemanticGraphBuilder.ts

@@ -167,6 +167,8 @@ const projectFile = (
             location: callable.location,
             label: callable.name,
             functionNodeId: null,
+            // The label is display text; keep the exact name, which may be "".
+            properties: { name: callable.name },
           },
           state,
         ),