require auth to log in (lock screen), remove auth-on-logout, remove welcome card from multicoin dashboard, relocate login buttons to root welcome page

- login('multi') no longer silently loads seed from keychain — shows locked screen with Touch ID/password
- Removed welcome card from EvmDashboard (multicoin route), root / handles account selection
- Root welcome page buttons call w.login() before navigating to respective routes
- Monero welcome page buttons also call w.login() before navigating
- logout now simply calls w.logout() + navigate('/') with no auth required
- Removed tab-bar logout buttons; logout moved to wallet card alongside refresh/settings/stop

apps/desktop/src/routes/monero/index.svelte

@@ -48,7 +48,7 @@
 				<CardContent>
 					<div class="flex flex-col gap-3">
 						<Button
-							onclick={() => navigate('/multicoin')}
+							onclick={async () => { await w.login('multi'); navigate('/multicoin') }}
 							variant="outline"
 							class="w-full">
 							Multi Coins (ETH / BSC / Polygon)
@@ -67,11 +67,6 @@
 					class="cursor-pointer rounded-md px-2.5 py-1 text-xs font-medium transition-colors bg-primary text-primary-foreground">
 					Monero
 				</button>
-				<button
-					class="cursor-pointer rounded-md px-2.5 py-1 text-xs font-medium transition-colors bg-muted text-muted-foreground hover:bg-muted/80"
-					onclick={() => w.logout()}>
-					Logout
-				</button>
 			</div>
 
 			{#if w.moneroDownloading}
@@ -214,6 +209,9 @@
 						<Button variant="outline" onclick={() => w.moneroStop()}>
 							Stop
 						</Button>
+						<Button variant="outline" onclick={() => { w.logout(); navigate('/') }}>
+							Logout
+						</Button>
 					</div>
 				</CardContent>
 			</Card>