feat(stats): inline 30-min sparklines on container CPU + memory bars

Always-visible trend lines next to the existing bars on every running
instance and static-site card so the user can spot a slow drift or recent
spike at a glance, without expanding the full history chart. Implemented
as a tiny pure-SVG component (no ECharts on hot list paths) — values are
fetched once per 30s alongside the current snapshot via a 30m history
query that the collector already serves.

- Sparkline.svelte: pure-SVG polyline + optional area fill, normalises
  values to [0,100] and clamps out-of-range points
- ContainerStats: parallel fetch of stats + 30m history, two new
  $derived arrays for CPU% and memory%, sparklines slotted between the
  bar and the numeric readout

web/src/lib/components/ContainerStats.svelte

@@ -9,6 +9,7 @@
 	import { t } from '$lib/i18n';
 	import { statsInterval } from '$lib/stores/statsInterval';
 	import ResourceChart from './ResourceChart.svelte';
+	import Sparkline from './Sparkline.svelte';
 	import type { EChartsOption } from 'echarts';
 
 	export type StatsSource =
@@ -24,6 +25,11 @@
 
 	let stats = $state<ContainerStats | null>(null);
 	let history = $state<ContainerStatsSample[]>([]);
+	// Short rolling window for the always-visible sparklines. Kept separate
+	// from `history` (which is sized to `historyWindow` and only loaded on
+	// expand) so the inline trend doesn't change zoom every time the user
+	// switches the chart range.
+	let sparkSamples = $state<ContainerStatsSample[]>([]);
 	let error = $state(false);
 	let expanded = $state(false);
 
@@ -34,17 +40,17 @@
 		return api.fetchStaticSiteStats(source.siteId, signal);
 	}
 
-	async function fetchHistory(signal: AbortSignal): Promise<ContainerStatsSample[]> {
+	async function fetchHistory(signal: AbortSignal, win: string = historyWindow): Promise<ContainerStatsSample[]> {
 		if (source.kind === 'instance') {
 			return api.fetchInstanceStatsHistory(
 				source.projectId,
 				source.stageId,
 				source.instanceId,
-				historyWindow,
+				win,
 				signal
 			);
 		}
-		return api.fetchStaticSiteStatsHistory(source.siteId, historyWindow, signal);
+		return api.fetchStaticSiteStatsHistory(source.siteId, win, signal);
 	}
 
 	$effect(() => {
@@ -54,8 +60,15 @@
 			controller.abort();
 			controller = new AbortController();
 			try {
-				const result = await fetchStats(controller.signal);
+				const [result, spark] = await Promise.all([
+					fetchStats(controller.signal),
+					// Always pull a 30-minute rolling window for the inline
+					// sparkline. Cheap query and gives the user a trend hint
+					// without forcing them to expand the full history chart.
+					fetchHistory(controller.signal, '30m').catch(() => [] as ContainerStatsSample[])
+				]);
 				stats = result;
+				sparkSamples = spark;
 				error = false;
 				if (expanded) {
 					history = await fetchHistory(controller.signal);
@@ -91,6 +104,14 @@
 		return 'bg-blue-500';
 	});
 
+	// CPU samples normalize to absolute percent (already 0-100 from the
+	// collector). Memory samples need percent-of-limit so the sparkline
+	// matches the bar's denominator.
+	const cpuSpark = $derived(sparkSamples.map((s) => s.cpu_percent));
+	const memSpark = $derived(
+		sparkSamples.map((s) => (s.memory_limit > 0 ? (s.memory_usage / s.memory_limit) * 100 : 0))
+	);
+
 	const historyOption = $derived<EChartsOption>({
 		animation: false,
 		grid: { top: 8, right: 10, bottom: 24, left: 40 },
@@ -139,7 +160,7 @@
 
 {#if stats}
 	<div class="mt-2 space-y-1">
-		<!-- CPU bar -->
+		<!-- CPU bar + 30m sparkline -->
 		<div class="flex items-center gap-2">
 			<span class="w-8 text-[10px] font-medium text-[var(--text-tertiary)]">{$t('stats.cpu')}</span>
 			<div class="relative h-1.5 flex-1 overflow-hidden rounded-full bg-[var(--surface-card-hover)]">
@@ -148,11 +169,14 @@
 					style="width: {Math.min(stats.cpu_percent, 100)}%"
 				></div>
 			</div>
+			<span class="text-emerald-500 dark:text-emerald-400" aria-hidden="true">
+				<Sparkline values={cpuSpark} width={64} height={14} color="currentColor" fill="rgba(16,185,129,0.18)" ariaLabel={$t('resources.cpuSeries')} />
+			</span>
 			<span class="w-10 text-right text-[10px] tabular-nums text-[var(--text-tertiary)]">
 				{stats.cpu_percent.toFixed(1)}%
 			</span>
 		</div>
-		<!-- Memory bar -->
+		<!-- Memory bar + 30m sparkline -->
 		<div class="flex items-center gap-2">
 			<span class="w-8 text-[10px] font-medium text-[var(--text-tertiary)]">{$t('stats.mem')}</span>
 			<div class="relative h-1.5 flex-1 overflow-hidden rounded-full bg-[var(--surface-card-hover)]">
@@ -161,6 +185,9 @@
 					style="width: {Math.min(stats.memory_percent, 100)}%"
 				></div>
 			</div>
+			<span class="text-blue-500 dark:text-blue-400" aria-hidden="true">
+				<Sparkline values={memSpark} width={64} height={14} color="currentColor" fill="rgba(59,130,246,0.18)" ariaLabel={$t('resources.memorySeries')} />
+			</span>
 			<span class="w-24 text-right text-[10px] tabular-nums text-[var(--text-tertiary)]">
 				{formatBytes(stats.memory_usage)} / {formatBytes(stats.memory_limit)}
 			</span>

web/src/lib/components/Sparkline.svelte

@@ -0,0 +1,71 @@
+<!--
+  Tiny inline sparkline. Pure SVG so we don't pull ECharts into hot
+  list-view paths just to draw a 12px-tall trend line. Values are expected
+  pre-normalized to [0, 100]; out-of-range points clamp.
+-->
+<script lang="ts">
+	interface Props {
+		values: number[];
+		width?: number;
+		height?: number;
+		color?: string;
+		fill?: string;
+		ariaLabel?: string;
+	}
+
+	const {
+		values,
+		width = 80,
+		height = 14,
+		color = 'currentColor',
+		fill = 'transparent',
+		ariaLabel = ''
+	}: Props = $props();
+
+	const points = $derived.by(() => {
+		const n = values.length;
+		if (n === 0) return '';
+		if (n === 1) {
+			const y = height - (clamp(values[0]) / 100) * height;
+			return `0,${y.toFixed(2)} ${width},${y.toFixed(2)}`;
+		}
+		const step = width / (n - 1);
+		return values
+			.map((v, i) => {
+				const x = (i * step).toFixed(2);
+				const y = (height - (clamp(v) / 100) * height).toFixed(2);
+				return `${x},${y}`;
+			})
+			.join(' ');
+	});
+
+	const fillPath = $derived.by(() => {
+		if (!values.length || fill === 'transparent') return '';
+		return `M0,${height} L${points.replace(/,/g, ' ').replace(/ /g, ',')} L${width},${height} Z`
+			.replace(/L,/, 'L');
+	});
+
+	function clamp(v: number): number {
+		if (!Number.isFinite(v)) return 0;
+		if (v < 0) return 0;
+		if (v > 100) return 100;
+		return v;
+	}
+</script>
+
+<svg
+	{width}
+	{height}
+	viewBox="0 0 {width} {height}"
+	preserveAspectRatio="none"
+	role="img"
+	aria-label={ariaLabel}
+	class="block"
+>
+	{#if values.length > 0}
+		{#if fill !== 'transparent'}
+			<polygon points="0,{height} {points} {width},{height}" fill={fill} stroke="none" />
+		{/if}
+		<polyline points={points} fill="none" stroke={color} stroke-width="1.25" stroke-linejoin="round" stroke-linecap="round" />
+	{/if}
+</svg>