Add user database migration, core reusable components, and layout structure

web/lib/auth.mjs

@@ -0,0 +1,49 @@
+const TOKEN_KEY = 'wo_token';
+const USER_KEY  = 'wo_user';
+
+export function getToken() {
+  return localStorage.getItem(TOKEN_KEY) || '';
+}
+
+export function setToken(token) {
+  localStorage.setItem(TOKEN_KEY, token);
+  try {
+    const payload = JSON.parse(atob(token.split('.')[1]));
+    localStorage.setItem(USER_KEY, JSON.stringify({
+      id:          payload.uid,
+      username:    payload.username,
+      email:       payload.email,
+      displayName: payload.name,
+      role:        payload.role,
+    }));
+  } catch { /* ignore decode errors */ }
+}
+
+export function clearToken() {
+  localStorage.removeItem(TOKEN_KEY);
+  localStorage.removeItem(USER_KEY);
+}
+
+export function getUser() {
+  const token = getToken();
+  if (!token) return null;
+  try {
+    const payload = JSON.parse(atob(token.split('.')[1]));
+    if (payload.exp && payload.exp * 1000 < Date.now()) {
+      clearToken();
+      return null;
+    }
+    const stored = localStorage.getItem(USER_KEY);
+    return stored ? JSON.parse(stored) : null;
+  } catch {
+    return null;
+  }
+}
+
+const ROLE_LEVEL = { admin: 4, dispatcher: 3, field_tech: 2, viewer: 1 };
+
+export function hasRole(minRole) {
+  const user = getUser();
+  if (!user) return false;
+  return (ROLE_LEVEL[user.role] || 0) >= (ROLE_LEVEL[minRole] || 0);
+}