feat(integrations): say where an imported Google Health history ends

The two status routes publish backfillEnded: each data type whose
backfill stopped short of the start of its history, with the instant it
reaches back to and whether the horizon or a walk that stopped moving
ended it. The integration card lists them in place of an import that
would otherwise read as still loading, in all seven locales.

Refs #1220

src/components/settings/integrations/shared.tsx

@@ -54,6 +54,15 @@ export interface IntegrationStatusViewModel {
   connected?: boolean;
   /** WHOOP / Fitbit / Google Health: older history still loading. */
   backfillCompleted?: boolean | null;
+  /**
+   * Google Health: data types whose history backfill ended before the start
+   * of their history, with where and why.
+   */
+  backfillEnded?: Array<{
+    type: string;
+    endsAt: string;
+    reason: "horizon" | "no_progress";
+  }>;
   /**
    * Polar / Oura / Strava: usable credentials resolve (BYO or the shared
    * app). Greys out "Connect" when false.