feat(EMBEDDINGS-0001): add save feedback banners and fix Svelte 5 runes compliance

Replace onMount with $effect for initial config loading. Add auto-dismissing
green success banner (3 s) and persistent red error banner after save attempts.
Remove inline status text in favour of full-width banners with icons.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/routes/settings/+page.svelte

@@ -1,6 +1,5 @@
 <script lang="ts">
 	import StatBadge from '$lib/components/StatBadge.svelte';
-	import { onMount } from 'svelte';
 
 	// ---------------------------------------------------------------------------
 	// Provider presets
@@ -49,13 +48,16 @@
 	let loading = $state(true);
 
 	// ---------------------------------------------------------------------------
-	// Load current config on mount
+	// Load current config + probe local provider on mount (Svelte 5 $effect)
 	// ---------------------------------------------------------------------------
 
-	onMount(async () => {
+	$effect(() => {
+		let cancelled = false;
+
+		(async () => {
 			try {
 				const res = await fetch('/api/v1/settings/embedding');
-			if (res.ok) {
+				if (!cancelled && res.ok) {
 					const data = await res.json();
 					provider = data.provider ?? 'none';
 					if (data.openai) {
@@ -68,7 +70,7 @@
 			} catch {
 				// Non-fatal — fall back to defaults
 			} finally {
-			loading = false;
+				if (!cancelled) loading = false;
 			}
 
 			// Probe whether the local provider is available
@@ -78,9 +80,24 @@
 					headers: { 'Content-Type': 'application/json' },
 					body: JSON.stringify({ provider: 'local' })
 				});
-			localAvailable = res.ok;
+				if (!cancelled) localAvailable = res.ok;
 			} catch {
-			localAvailable = false;
+				if (!cancelled) localAvailable = false;
+			}
+		})();
+
+		return () => {
+			cancelled = true;
+		};
+	});
+
+	// Auto-dismiss save success banner after 3 seconds
+	$effect(() => {
+		if (saveStatus === 'ok') {
+			const timer = setTimeout(() => {
+				saveStatus = 'idle';
+			}, 3000);
+			return () => clearTimeout(timer);
 		}
 	});
 
@@ -292,14 +309,49 @@
 			</div>
 		{/if}
 
-		<!-- Save row -->
-		<div class="mt-6 flex items-center justify-end gap-3">
+		<!-- Save feedback banners -->
 		{#if saveStatus === 'ok'}
-				<span class="text-sm text-green-600">Settings saved.</span>
+			<div
+				class="mt-4 flex items-center gap-2 rounded-lg border border-green-200 bg-green-50 px-4 py-3 text-sm font-medium text-green-700"
+			>
+				<svg
+					xmlns="http://www.w3.org/2000/svg"
+					class="h-4 w-4 shrink-0"
+					viewBox="0 0 20 20"
+					fill="currentColor"
+					aria-hidden="true"
+				>
+					<path
+						fill-rule="evenodd"
+						d="M16.707 5.293a1 1 0 010 1.414l-8 8a1 1 0 01-1.414 0l-4-4a1 1 0 011.414-1.414L8 12.586l7.293-7.293a1 1 0 011.414 0z"
+						clip-rule="evenodd"
+					/>
+				</svg>
+				Settings saved successfully.
+			</div>
 		{:else if saveStatus === 'error'}
-				<span class="text-sm text-red-600">{saveError}</span>
+			<div
+				class="mt-4 flex items-center gap-2 rounded-lg border border-red-200 bg-red-50 px-4 py-3 text-sm font-medium text-red-700"
+			>
+				<svg
+					xmlns="http://www.w3.org/2000/svg"
+					class="h-4 w-4 shrink-0"
+					viewBox="0 0 20 20"
+					fill="currentColor"
+					aria-hidden="true"
+				>
+					<path
+						fill-rule="evenodd"
+						d="M18 10a8 8 0 11-16 0 8 8 0 0116 0zm-7 4a1 1 0 11-2 0 1 1 0 012 0zm-1-9a1 1 0 00-1 1v4a1 1 0 102 0V6a1 1 0 00-1-1z"
+						clip-rule="evenodd"
+					/>
+				</svg>
+				{saveError}
+			</div>
 		{/if}
 
+		<!-- Save row -->
+		<div class="mt-4 flex items-center justify-end">
 			<button
 				onclick={save}
 				disabled={saving}