feat(healthkit): record Apple Health dose arrivals and the last background arrival per type

Migration 0401 turns healthkit_type_syncs.type into text so the ledger can
hold MEDICATION_DOSE, and adds last_background_at (seeded from rows whose
latest arrival was a background one). POST /api/medications/intake/bulk
takes syncTrigger and records APPLE_HEALTH dose arrivals; the Apple Health
status read serves a MEDICATION_DOSE freshness entry and lastBackgroundAt
on every entry with arrival facts.

src/components/settings/integrations/apple-health-card.tsx

@@ -133,7 +133,8 @@ function DeliveryDiagnostic({
  * under which trigger, and when one last brought a new value. The newest
  * sample's time on the right of the row says when the reading was TAKEN; this
  * says when the server RECEIVED it, which is what tells a type that only
- * arrives on "Sync all" from one the phone delivers by itself (#1173). Nothing
+ * arrives on "Sync all" from one the phone delivers by itself (#1173), plus
+ * the last background arrival when a later one came another way. Nothing
  * renders when the server sent no arrival facts (the workouts row, or a failed
  * ledger read), so absence is never painted as "not received".
  */
@@ -176,6 +177,18 @@ export function ArrivalDetail({
       }),
     );
   }
+  // The last background arrival, when a later one came another way: opening
+  // the app to look would otherwise hide that the phone delivers by itself.
+  if (
+    entry.lastBackgroundAt &&
+    entry.lastBackgroundAt !== entry.lastReceivedAt
+  ) {
+    parts.push(
+      t("settings.appleHealth.freshness.lastBackground", {
+        relative: relative(entry.lastBackgroundAt),
+      }),
+    );
+  }
   return (
     <span
       data-testid="apple-health-arrival"

src/components/settings/integrations/metric-freshness-list.tsx

@@ -30,6 +30,8 @@ import { cn } from "@/lib/utils";
 
 /** The pseudo-type carrying a source's newest workout. */
 const WORKOUT_TYPE = "WORKOUTS";
+/** The pseudo-type carrying Apple Health medication doses. */
+const MEDICATION_DOSE_TYPE = "MEDICATION_DOSE";
 
 /**
  * Turn an unmapped enum name into something readable. `MEASUREMENT_TYPE_LABEL_KEYS`
@@ -68,6 +70,8 @@ export function MetricFreshnessList<
   const label = (type: string): string => {
     if (type === WORKOUT_TYPE)
       return t("settings.integrationFreshness.workouts");
+    if (type === MEDICATION_DOSE_TYPE)
+      return t("settings.integrationFreshness.medicationDoses");
     const key = MEASUREMENT_TYPE_LABEL_KEYS[type];
     return key ? t(key) : humanise(type);
   };