fix(javascript): preserve source facts across graph projections

src/domain/javascript/javascriptArtifactFiles.ts

@@ -1,6 +1,18 @@
+import { z } from "zod";
+import { digestSchema } from "../digests.js";
 import type { JavaScriptSourceSelection } from "./javascriptSourceSelection.js";
 import type { ArtifactOccurrence } from "../artifactGraph.js";
 
+/** One physical file occurrence, independent of its graph representations. */
+export const javaScriptFileOccurrenceSchema = z.strictObject({
+  container_sha256: digestSchema,
+  path: z.string().min(1),
+  sha256: digestSchema,
+});
+export type JavaScriptFileOccurrence = z.infer<
+  typeof javaScriptFileOccurrenceSchema
+>;
+
 /** Whether an inventoried path has a source extension read by the analyzer. */
 export const isJavaScriptSourcePath = (path: string): boolean =>
   /\.(?:cjs|cts|mjs|mts|js|jsx|ts|tsx)$/iu.test(path);