Scaffold the mobile member app: PWA shell, push, and app-shell tokens

New `mobile` Django app mounted at /app/ -- the installed PWA for Member
mode (M1-M7, see design_handoff_rosterchief_platform/README.md). Coach
mode (C1-C6) is a later phase and has no routes yet.

Foundation pieces:
- assets/mobile.css: Tailwind v4 theme reusing management.css's design
  tokens (same per-club --tenant-* theming pattern), plus the ice/coach
  accent and mobile's 14px card radius.
- PushSubscription model + pywebpush-based sender (mobile/services/push.py),
  wired to notifications.Notification via a post_save signal so the
  existing notification system gains a push channel without knowing about
  PWAs itself.
- Per-club manifest.webmanifest + service worker (served at /app/sw.js)
  + a server-rendered fallback home-screen icon (club initials on
  secondary_color) for clubs without an uploaded logo -- confirmed with
  the user as the fallback, never a generic RosterChief mark.
- App shell (base.html): navy header, person switcher (every child a
  signed-in parent manages, plus "Me"), bottom tab bar, safe-area insets.
  Vendored htmx + Alpine for the screens built on top of it.
- Placeholder views/routes for all seven M1-M7 screens so the shell is
  fully wired end-to-end before each screen is built out individually.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01ECGMEwrc2k4D8VQuwjstj9

static/css/app.css

@@ -2774,6 +2774,9 @@
   .right-0 {
     right: 0;
   }
+  .right-1\.5 {
+    right: calc(var(--spacing) * 1.5);
+  }
   .right-2 {
     right: calc(var(--spacing) * 2);
   }
@@ -3853,6 +3856,9 @@
   .h-1\.5 {
     height: calc(var(--spacing) * 1.5);
   }
+  .h-2 {
+    height: calc(var(--spacing) * 2);
+  }
   .h-4 {
     height: calc(var(--spacing) * 4);
   }
@@ -3967,6 +3973,9 @@
   .w-1\.5 {
     width: calc(var(--spacing) * 1.5);
   }
+  .w-2 {
+    width: calc(var(--spacing) * 2);
+  }
   .w-4 {
     width: calc(var(--spacing) * 4);
   }
@@ -4741,6 +4750,9 @@
   .pt-4 {
     padding-top: calc(var(--spacing) * 4);
   }
+  .pb-0\.5 {
+    padding-bottom: calc(var(--spacing) * 0.5);
+  }
   .pb-2 {
     padding-bottom: calc(var(--spacing) * 2);
   }
@@ -4858,6 +4870,9 @@
   .text-\[17px\] {
     font-size: 17px;
   }
+  .text-\[19px\] {
+    font-size: 19px;
+  }
   .text-\[22px\] {
     font-size: 22px;
   }
@@ -5260,6 +5275,13 @@
       --btn-soft-bg: initial;
     }
   }
+  .btn-secondary {
+    @layer daisyui.l1.l2 {
+      --btn-color: var(--color-secondary);
+      --btn-fg: var(--color-secondary-content);
+      --btn-soft-bg: initial;
+    }
+  }
   .btn-sm {
     @layer daisyui.l1.l2 {
       --fontsize: 0.75rem;

static/js/mobile-app.js

@@ -0,0 +1,55 @@
+// RosterChief member app -- registers the service worker and exposes
+// window.rosterchiefPush.{subscribe,unsubscribe}() for M7 (Notifications)
+// to wire a permission-request button to (browsers require a user gesture
+// before Notification.requestPermission() will prompt, so this is never
+// called automatically on page load).
+
+if ("serviceWorker" in navigator) {
+    window.addEventListener("load", () => navigator.serviceWorker.register("/app/sw.js"));
+}
+
+function urlBase64ToUint8Array(base64String) {
+    const padding = "=".repeat((4 - (base64String.length % 4)) % 4);
+    const base64 = (base64String + padding).replace(/-/g, "+").replace(/_/g, "/");
+    const raw = window.atob(base64);
+    return Uint8Array.from([...raw].map((char) => char.charCodeAt(0)));
+}
+
+async function subscribe() {
+    if (!("serviceWorker" in navigator) || !("PushManager" in window)) return false;
+
+    const permission = await Notification.requestPermission();
+    if (permission !== "granted") return false;
+
+    const publicKey = document.body.dataset.vapidPublicKey;
+    if (!publicKey) return false;
+
+    const registration = await navigator.serviceWorker.ready;
+    const subscription = await registration.pushManager.subscribe({
+        userVisibleOnly: true,
+        applicationServerKey: urlBase64ToUint8Array(publicKey),
+    });
+
+    await fetch("/app/push/subscribe/", {
+        method: "POST",
+        headers: { "Content-Type": "application/json", "X-CSRFToken": document.body.dataset.csrftoken || "" },
+        body: JSON.stringify(subscription.toJSON()),
+    });
+    return true;
+}
+
+async function unsubscribe() {
+    if (!("serviceWorker" in navigator)) return;
+    const registration = await navigator.serviceWorker.ready;
+    const subscription = await registration.pushManager.getSubscription();
+    if (!subscription) return;
+
+    await fetch("/app/push/subscribe/", {
+        method: "DELETE",
+        headers: { "Content-Type": "application/json", "X-CSRFToken": document.body.dataset.csrftoken || "" },
+        body: JSON.stringify({ endpoint: subscription.endpoint }),
+    });
+    await subscription.unsubscribe();
+}
+
+window.rosterchiefPush = { subscribe, unsubscribe };