feat: add streak counter to rosary page

Track daily rosary prayer streaks using localStorage. Shows consecutive
days prayed and disables button if already prayed today.

src/lib/components/StreakCounter.svelte

@@ -0,0 +1,98 @@
+<script lang="ts">
+import { browser } from '$app/environment';
+import { getRosaryStreak } from '$lib/stores/rosaryStreak.svelte';
+
+const streak = browser ? getRosaryStreak() : null;
+</script>
+
+<div class="streak-container">
+	<div class="streak-display">
+		<span class="streak-number">{streak?.length ?? 0}</span>
+		<span class="streak-label">Tage</span>
+	</div>
+	<button
+		class="streak-button"
+		onclick={() => streak?.recordPrayer()}
+		disabled={streak?.prayedToday}
+		aria-label="Gebet als gebetet markieren"
+	>
+		{#if streak?.prayedToday}
+			Heute gebetet
+		{:else}
+			Gebetet
+		{/if}
+	</button>
+</div>
+
+<style>
+.streak-container {
+	display: flex;
+	align-items: center;
+	gap: 1.5rem;
+	padding: 1rem 1.5rem;
+	background: var(--nord1);
+	border-radius: 12px;
+	width: fit-content;
+}
+
+@media (prefers-color-scheme: light) {
+	.streak-container {
+		background: var(--nord5);
+	}
+}
+
+.streak-display {
+	display: flex;
+	flex-direction: column;
+	align-items: center;
+}
+
+.streak-number {
+	font-size: 2.5rem;
+	font-weight: 700;
+	color: var(--nord13);
+	line-height: 1;
+}
+
+.streak-label {
+	font-size: 0.85rem;
+	color: var(--nord4);
+	text-transform: uppercase;
+	letter-spacing: 0.05em;
+}
+
+@media (prefers-color-scheme: light) {
+	.streak-label {
+		color: var(--nord3);
+	}
+}
+
+.streak-button {
+	padding: 0.75rem 1.5rem;
+	border: none;
+	border-radius: 8px;
+	background: var(--nord10);
+	color: white;
+	font-size: 1rem;
+	font-weight: 600;
+	cursor: pointer;
+	transition: all 0.2s ease;
+}
+
+.streak-button:hover:not(:disabled) {
+	background: var(--nord9);
+	transform: translateY(-2px);
+}
+
+.streak-button:disabled {
+	background: var(--nord3);
+	cursor: default;
+	opacity: 0.7;
+}
+
+@media (prefers-color-scheme: light) {
+	.streak-button:disabled {
+		background: var(--nord4);
+	}
+}
+</style>