fix: home "Vaccine Reminder" showing "undefined due today"

The home banner read fields (.status, .vaccineName) that the DB-backed
notifications API never returns — its DTO exposes {type, title, message,
metadata,...}. So .vaccineName was undefined → "undefined due today", and
.status was undefined → the ternary always fell to the "due today" branch
even for overdue/nudge items.

Two issues, both fixed:
1. Contract mismatch: render the real `message` field instead of the
   non-existent `.vaccineName`/`.status`. message is already correctly built
   server-side ("BCG is due today" / "BCG is 3 days overdue").
2. Wrong source set: the banner consumed the FIRST notification of ANY type.
   Since the API also returns log/memory/garment nudges, a nudge could land
   at index 0 and render under the vaccine header. Now filtered to
   type starting with "vaccine_" before use.

Also hardened the vaccine upsert: ON CONFLICT DO NOTHING -> DO UPDATE SET
title/message/action_url/metadata, so future copy/day-count changes refresh
existing rows instead of freezing the first version (preserves id/is_read).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/app/(app)/home/page.tsx

@@ -125,7 +125,11 @@ export default function HomePage() {
     window.addEventListener("online", handleOnline);
     fetch(`/api/notifications?childId=${childId}`)
       .then(res => res.json())
-      .then(data => setVaccineReminders(data.notifications || []))
+      // Only vaccine notifications belong in the "Vaccine Reminder" banner —
+      // the API also returns log/memory/garment nudges.
+      .then(data => setVaccineReminders(
+        (data.notifications || []).filter((n: { type?: string }) => n.type?.startsWith("vaccine_"))
+      ))
       .catch(console.error);
     return () => window.removeEventListener("online", handleOnline);
   }, [childId]);

src/app/api/notifications/route.ts

@@ -83,12 +83,6 @@ export async function GET(request: NextRequest) {
     const child     = children[0];
     const birthDate = new Date(child.birth_date as string);
 
-    // Self-heal legacy data: an earlier generator stored "undefined" in the
-    // message ("undefined is N days overdue"). Those rows were frozen by
-    // ON CONFLICT DO NOTHING. Delete them so the upsert below regenerates them
-    // with the correct vaccine name.
-    await sql`DELETE FROM notifications WHERE family_id = ${familyId} AND message LIKE 'undefined%'`;
-
     // ── 1. Vaccine notifications ──────────────────────────────────────────────
     const given = await sql`
       SELECT vaccine_name FROM vaccinations