refactor: auto-prompt for notification permission, drop OT alerts button

Browsers already gate Notification.requestPermission behind a native
prompt, so a dedicated button was redundant UI clutter. Prompting on
load (only when permission state is "default") keeps the flow and
clears space in the banner for future notification types.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

app/static/styles.css

@@ -453,37 +453,6 @@ main {
     font-weight: 700;
 }
 
-.banner-notify {
-    background: rgba(212, 175, 55, 0.08);
-    border: 1px solid var(--cup-gold-dim);
-    color: var(--cup-gold-2);
-    font-size: 0.7rem;
-    font-weight: 700;
-    letter-spacing: 0.08em;
-    text-transform: uppercase;
-    padding: 0.45rem 0.7rem;
-    border-radius: 999px;
-    cursor: pointer;
-    white-space: nowrap;
-    transition: background 120ms ease, border-color 120ms ease;
-}
-
-.banner-notify:hover {
-    background: rgba(212, 175, 55, 0.18);
-    border-color: var(--cup-gold-1);
-}
-
-.banner-notify[data-perm="granted"] {
-    background: rgba(212, 175, 55, 0.2);
-    border-color: var(--cup-gold-1);
-    color: var(--cup-gold-2);
-}
-
-.banner-notify[data-perm="denied"] {
-    opacity: 0.5;
-    cursor: not-allowed;
-}
-
 @media (min-width: 900px) {
     .playoff-banner {
         padding: 1.125rem 2rem;