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/JavaScriptArtifactGraphAccumulator.ts

@@ -68,25 +68,19 @@ const observationInput = (
 
 /** Node fields whose display form is normalized before validation. */
 interface DisplayableNodeInput {
-  readonly identity: {
-    readonly strategy: string;
-    readonly key?: string;
-    readonly original_source?: string;
-  };
   readonly observations: readonly { readonly label: string | null }[];
 }
 
 /**
  * Static findings can carry legal empty strings, such as `fetch("")`,
- * `require("")`, or a source map's `sources: [""]`. Labels, artifact-local
- * keys, and original source names must be nonempty, so display the empty value
- * as `""`; each observation keeps the exact value in its properties.
+ * `require("")`, or a source map's `sources: [""]`. Labels are nonempty display
+ * text, so the empty value is shown as `""`. Identities and observation
+ * properties keep the exact value, so distinct values never merge.
  */
 const displayableNode = (
   input: DisplayableNodeInput,
 ): DisplayableNodeInput => ({
   ...input,
-  identity: displayableIdentity(input.identity),
   observations: input.observations.map((observation) => ({
     ...observation,
     label:
@@ -95,19 +89,3 @@ const displayableNode = (
         : javascriptDisplayText(observation.label),
   })),
 });
-
-const displayableIdentity = (
-  identity: DisplayableNodeInput["identity"],
-): DisplayableNodeInput["identity"] => {
-  if (identity.strategy === "artifact-local-key" && identity.key !== undefined)
-    return { ...identity, key: javascriptDisplayText(identity.key) };
-  if (
-    identity.strategy === "source-map-original" &&
-    identity.original_source !== undefined
-  )
-    return {
-      ...identity,
-      original_source: javascriptDisplayText(identity.original_source),
-    };
-  return identity;
-};