Add account settings page with profile, password, and session management

- /account page: edit name/email, change password, view/revoke sessions
- PATCH /api/account: update profile or change password (verifies current)
- DELETE /api/account: revoke all other sessions
- Password change auto-revokes other sessions for security
- Username in nav now links to /account (desktop + mobile)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/routes/+layout.svelte

@@ -70,7 +70,7 @@
 								Admin
 							</a>
 						{/if}
-						<span class="text-white/80 text-sm">{data.user.name}</span>
+						<a href="/account" class="text-white/80 text-sm hover:text-white transition">{data.user.name}</a>
 						<NotificationBell />
 						<button
 							onclick={async () => {
@@ -142,7 +142,7 @@
 						<SearchBar />
 					</div>
 					<div class="flex flex-col gap-1">
-						<span class="text-white/80 text-sm py-1">{data.user.name}</span>
+						<a href="/account" class="text-white/80 text-sm py-1 hover:text-white transition" onclick={() => (mobileMenuOpen = false)}>{data.user.name}</a>
 						{#if data.user.tenantRole === 'ADMIN' || data.user.globalRole === 'SITE_ADMIN'}
 							<a
 								href="/admin"