Add web client

Join screen, room with screen and camera sharing, live annotation,
whiteboard, and the admin panel for kiosks, widgets and branding.

apps/web-client/src/lib/session.ts

@@ -0,0 +1,60 @@
+import type { JoinResponse } from "@pistation/shared-types";
+import { browser } from "$app/environment";
+
+const SESSION_KEY = "pistation.session";
+const ADMIN_KEY = "pistation.admin";
+
+export type StoredSession = JoinResponse;
+
+export function saveSession(session: StoredSession): void {
+  if (!browser) return;
+  sessionStorage.setItem(SESSION_KEY, JSON.stringify(session));
+}
+
+export function loadSession(): StoredSession | null {
+  if (!browser) return null;
+  const raw = sessionStorage.getItem(SESSION_KEY);
+  if (!raw) return null;
+  try {
+    return JSON.parse(raw) as StoredSession;
+  } catch {
+    return null;
+  }
+}
+
+export function clearSession(): void {
+  if (!browser) return;
+  sessionStorage.removeItem(SESSION_KEY);
+}
+
+export interface StoredAdmin {
+  accessToken: string;
+  email: string;
+  expiresAt: number;
+}
+
+export function saveAdmin(admin: StoredAdmin): void {
+  if (!browser) return;
+  localStorage.setItem(ADMIN_KEY, JSON.stringify(admin));
+}
+
+export function loadAdmin(): StoredAdmin | null {
+  if (!browser) return null;
+  const raw = localStorage.getItem(ADMIN_KEY);
+  if (!raw) return null;
+  try {
+    const admin = JSON.parse(raw) as StoredAdmin;
+    if (admin.expiresAt <= Date.now()) {
+      localStorage.removeItem(ADMIN_KEY);
+      return null;
+    }
+    return admin;
+  } catch {
+    return null;
+  }
+}
+
+export function clearAdmin(): void {
+  if (!browser) return;
+  localStorage.removeItem(ADMIN_KEY);
+}