Web Push: goal, kickoff and full-time alerts for a followed team

Fully progressive: without VAPID keys in the environment the API says
404, the bell never renders, and the service worker addition (a push
handler via workbox importScripts — no SW strategy change) is inert.
With keys: a bell on each team page requests permission, subscribes
(one team per device) and the server diffs fixture states on every
broadcast to push Kickoff / Goal / Full time to that team's followers.
Dead endpoints (404/410) self-clean. Round-trip verified locally with
dev VAPID keys; disabled mode verified too.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

src/lib/i18n/en.ts

@@ -409,6 +409,9 @@ export const en = {
     allTeams: "All teams",
     follow: "Follow this team",
     unfollow: "Unfollow this team",
+    notifyOn: "Get goal alerts for this team",
+    notifyOff: "Stop goal alerts",
+    notifyDenied: "Notifications are blocked in your browser settings.",
     eloBadge: "Elo {rating}",
     titleOddsBadge: "Title {pct}",
     advanceOddsBadge: "Advance {pct}",