refactor(dashboard): drop the duplicate band-builder export

buildTargetBands was a same-file alias of buildDashboardBands, which the
dead-code gate flags as a duplicate export. Keep the historic name only as
a re-export alias from the snapshot module, so callers and the parity test
are unchanged while bands.ts exposes a single builder.

src/lib/dashboard/bands.ts

@@ -135,9 +135,6 @@ export function buildDashboardBands(profile: {
   };
 }
 
-/**
- * Snapshot-era alias. The snapshot builder and its parity test still
- * import `buildTargetBands`; keep the name pointing at the canonical
- * builder so neither has to change.
- */
-export const buildTargetBands = buildDashboardBands;
+// The snapshot builder re-exports `buildDashboardBands` under the historic
+// `buildTargetBands` name (see dashboard/snapshot.ts) so callers and the
+// parity test keep working without a duplicate export living in this file.

src/lib/dashboard/snapshot.ts

@@ -78,7 +78,7 @@ import {
 } from "@/lib/dashboard/meds-today";
 import { computeUserHealthScoreFastPath } from "@/lib/analytics/health-score-fast-path";
 import {
-  buildTargetBands,
+  buildDashboardBands as buildTargetBands,
   type DashboardTargetBands,
 } from "@/lib/dashboard/bands";
 import type {