chore: finish frontend ESLint migration #18

Enable every plugin recommended preset and replace Biome with ESLint formatting.

Preserve API contracts and JSX whitespace; verify source, tests, builds and tooling.

src/test/resource.ts

@@ -1,21 +1,23 @@
 import type { paths } from "@/shared/api";
 
-type Meta =
-	paths["/api/v1/brokerage-accounts"]["get"]["responses"][200]["content"]["application/json"]["meta"];
+type Meta
+	= paths["/api/v1/brokerage-accounts"]["get"]["responses"][200]["content"]["application/json"]["meta"];
 function resource<T>(data: T, meta: Partial<Meta> = {}) {
-	return {
-		data,
-		meta: {
-			resourceKey: "fixture",
-			dataRevision: "1",
-			stateVersion: "1",
-			availability: data === null ? "missing" : "complete",
-			freshness: "fresh",
-			lastSuccessfulAt: "2026-08-14T00:00:00Z",
-			sync: { id: null, state: "idle", errorCode: null },
-			...meta,
-		} satisfies Meta,
-	};
+	return (/* eslint-disable unicorn/no-null -- Fixture preserves the production contract’s explicit null values. */
+		{
+			data,
+			meta: {
+				availability: data === null ? "missing" : "complete",
+				dataRevision: "1",
+				freshness: "fresh",
+				lastSuccessfulAt: "2026-08-14T00:00:00Z",
+				resourceKey: "fixture",
+				stateVersion: "1",
+				sync: { errorCode: null, id: null, state: "idle" },
+				...meta,
+			} satisfies Meta,
+		}
+	/* eslint-enable unicorn/no-null */);
 }
 
 export { resource };