Eng-council sweep: export hygiene, dead code, helper dedup, declare vega-expression

src/app/stores/ExtractStore.ts

@@ -31,7 +31,7 @@ interface InlineData {
  * none (no snippet, unparseable, or no `data.values`). The format comes from an
  * explicit `data.format.type` when present (raw CSV/TSV strings), else JSON.
  */
-export function readInlineData(draftText: string): InlineData | null {
+function readInlineData(draftText: string): InlineData | null {
   let parsed: unknown;
   try {
     parsed = JSON.parse(draftText);