add settings page with reset app: clears keychain secrets and SQLite cache

apps/desktop/src/routes/settings.svelte

@@ -0,0 +1,61 @@
+<script lang="ts">
+	import { wallet } from '$lib/states/wallet.svelte.js'
+	import { Button } from '$lib/components/ui/button/index.js'
+	import {
+		Card,
+		CardContent,
+		CardDescription,
+		CardHeader,
+		CardTitle,
+	} from '$lib/components/ui/card/index.js'
+	import { navigate } from 'sv-router/generated'
+
+	const w = wallet
+	let confirm = $state(false)
+	let resetting = $state(false)
+
+	async function handleReset() {
+		resetting = true
+		const ok = await w.resetApp()
+		if (ok) navigate('/')
+		resetting = false
+		confirm = false
+	}
+</script>
+
+<div class="mx-auto mt-16 max-w-md">
+	<div class="flex flex-col gap-4">
+		<Card>
+			<CardHeader>
+				<CardTitle>Settings</CardTitle>
+				<CardDescription>App preferences and data management</CardDescription>
+			</CardHeader>
+			<CardContent class="space-y-4">
+				<div>
+					<p class="font-medium text-xs">Reset App</p>
+					<p class="text-muted-foreground text-xs mt-1">
+						Removes your seed, API key, and all cached data from the keychain
+						and database. You can then set up the wallet fresh.
+					</p>
+					<div class="mt-3">
+						{#if confirm}
+							<div class="flex gap-2 items-center">
+								<p class="text-xs text-red-500">Are you sure?</p>
+								<Button size="sm" variant="destructive" onclick={handleReset} disabled={resetting}>
+									{resetting ? 'Resetting...' : 'Yes, reset everything'}
+								</Button>
+								<Button size="sm" variant="outline" onclick={() => (confirm = false)}>
+									Cancel
+								</Button>
+							</div>
+						{:else}
+							<Button variant="outline" onclick={() => (confirm = true)}>
+								Reset App
+							</Button>
+						{/if}
+					</div>
+				</div>
+			</CardContent>
+		</Card>
+	</div>
+</div>