Use a pinia store to manage account state

Refactor the existing scattered code dealing with the account state into
a pinia store.

components/Header.vue

@@ -8,18 +8,18 @@
 				<li>
 					<NuxtLink to="/schedule">Schedule</NuxtLink>
 				</li>
-				<li v-if="sessionStore.account?.type === 'admin' || sessionStore.account?.type === 'crew'">
+				<li v-if="accountStore.canEdit">
 					<NuxtLink to="/edit">Edit</NuxtLink>
 				</li>
 			</ul>
 		</nav>
 		<div class="account">
-			<template v-if="sessionStore.account">
-				{{ sessionStore.account.name }}
-				(s:{{ sessionStore.id }} a:{{ sessionStore.account.id }}{{ sessionStore.push ? " push" : null }})
-				{{ sessionStore.account.type }}
+			<template v-if="accountStore.valid">
+				{{ accountStore.name }}
+				(s:{{ sessionStore.id }} a:{{ accountStore.id }}{{ sessionStore.push ? " push" : null }})
+				{{ accountStore.type }}
 				<NuxtLink to="/account/settings">Settings</NuxtLink>
-				<LogOutButton v-if="sessionStore.account.type !== 'anonymous'"/>
+				<LogOutButton v-if="accountStore.type !== 'anonymous'"/>
 			</template>
 			<template v-else>
 				<NuxtLink to="/login">Log In</NuxtLink>
@@ -29,6 +29,7 @@
 </template>
 
 <script lang="ts" setup>
+const accountStore = useAccountStore();
 const sessionStore = useSessionStore();
 </script>