feat: cherry-pick PR #183 — multi-provider support, PWA, dynamic models, UI improvements

Cherry-picked from decolua/9router PR #183.
Note: open-sse changes included but need further review due to extensive modifications.

Co-authored-by: Cursor <cursoragent@cursor.com>

public/icons/icon-192.svg

@@ -0,0 +1,4 @@
+<svg xmlns="http://www.w3.org/2000/svg" width="192" height="192" viewBox="0 0 192 192">
+  <rect width="192" height="192" rx="24" fill="#0a0a0a"/>
+  <text x="96" y="120" font-family="Arial, sans-serif" font-size="80" font-weight="bold" fill="#ffffff" text-anchor="middle">9R</text>
+</svg>

public/icons/icon-512.svg

@@ -0,0 +1,4 @@
+<svg xmlns="http://www.w3.org/2000/svg" width="512" height="512" viewBox="0 0 512 512">
+  <rect width="512" height="512" rx="64" fill="#0a0a0a"/>
+  <text x="256" y="320" font-family="Arial, sans-serif" font-size="200" font-weight="bold" fill="#ffffff" text-anchor="middle">9R</text>
+</svg>

public/sw.js

@@ -0,0 +1,22 @@
+self.addEventListener('push', function (event) {
+  if (event.data) {
+    const data = event.data.json()
+    const options = {
+      body: data.body,
+      icon: data.icon || '/icons/icon-192.svg',
+      badge: '/icons/icon-192.svg',
+      vibrate: [100, 50, 100],
+      data: {
+        dateOfArrival: Date.now(),
+        primaryKey: '2',
+      },
+    }
+    event.waitUntil(self.registration.showNotification(data.title, options))
+  }
+})
+
+self.addEventListener('notificationclick', function (event) {
+  console.log('Notification click received.')
+  event.notification.close()
+  event.waitUntil(clients.openWindow('/'))
+})