Settings redesign: hub-based navigation, plus hardening and bug fixes

Rework the settings app around hub pages (home, network, displays, input,
apps, privacy, system) with a redesigned sidebar, shared nav state, and new
hub view components. Alongside the redesign: validate webview inputs into
root commands (users, firewall, snapshots, wifi), fix set_charge_threshold
writing the percentage via tee stdin, prevent streaming installs from
hanging on inherited stdin, add frontend type fixes, sync versions to
0.8.2, and clean up clippy/svelte-check warnings.

frontend/src/lib/components/SliderField.svelte

@@ -0,0 +1,44 @@
+<script lang="ts">
+	import Row from "./Row.svelte";
+
+	let {
+		label,
+		hint,
+		value = $bindable(),
+		min,
+		max,
+		step = 1,
+		suffix = "",
+		onChange,
+	}: {
+		label: string;
+		hint?: string;
+		value: number;
+		min: number;
+		max: number;
+		step?: number;
+		suffix?: string;
+		onChange?: () => void;
+	} = $props();
+
+	let shown = $derived(step < 1 ? Number(value).toFixed(2).replace(/0+$/, "").replace(/\.$/, "") : String(Math.round(value)));
+</script>
+
+<Row {label} {hint}>
+	<input type="range" {min} {max} {step} bind:value oninput={() => onChange?.()} />
+	<span class="val">{shown}{suffix}</span>
+</Row>
+
+<style>
+	input[type="range"] {
+		width: 160px;
+		accent-color: var(--accent);
+	}
+
+	.val {
+		min-width: 4.5ch;
+		text-align: right;
+		font-size: 12px;
+		color: var(--muted);
+	}
+</style>