feat(service-integrations): phase 2 — integration widget & app form UI

- Add 6 renderer components: StatCard, Gauge, List, Progress, AlertBanner, Chart
- Add IntegrationWidget container with auto-refresh, loading, error states
- Add IntegrationAlertOverlay for layout-level critical alerts
- Add IntegrationConfigFields for dynamic form generation from Zod schemas
- Register integration type in WidgetRenderer
- Extend WidgetCreationForm with integration app/endpoint pickers
- Extend AppForm with integration config section and test connection button
- Add /api/integrations/alerts endpoint

src/lib/components/app/IntegrationConfigFields.svelte

@@ -0,0 +1,57 @@
+<script lang="ts">
+	import type { IntegrationFieldDescriptor } from '$lib/server/integrations/types.js';
+
+	interface Props {
+		fields: IntegrationFieldDescriptor[];
+		values: Record<string, unknown>;
+		onchange: (name: string, value: unknown) => void;
+		idPrefix?: string;
+	}
+
+	let { fields, values, onchange, idPrefix = 'int' }: Props = $props();
+
+	const inputClass = 'w-full rounded-lg border border-input bg-background px-3 py-2 text-sm text-foreground placeholder:text-muted-foreground transition-colors focus:border-primary focus:outline-none focus:ring-2 focus:ring-ring/30';
+</script>
+
+<div class="space-y-3">
+	{#each fields as field (field.name)}
+		<div>
+			<label for="{idPrefix}-{field.name}" class="mb-1 block text-sm font-medium text-card-foreground">
+				{field.label}
+				{#if field.required}
+					<span class="text-destructive">*</span>
+				{/if}
+			</label>
+			{#if field.type === 'boolean'}
+				<label class="flex items-center gap-2">
+					<input
+						id="{idPrefix}-{field.name}"
+						type="checkbox"
+						checked={!!values[field.name]}
+						onchange={(e) => onchange(field.name, e.currentTarget.checked)}
+						class="h-4 w-4 rounded border-input accent-primary"
+					/>
+					<span class="text-sm text-muted-foreground">{field.description ?? ''}</span>
+				</label>
+			{:else if field.type === 'number'}
+				<input
+					id="{idPrefix}-{field.name}"
+					type="number"
+					value={values[field.name] ?? ''}
+					oninput={(e) => onchange(field.name, parseInt(e.currentTarget.value) || 0)}
+					class={inputClass}
+					placeholder={field.description ?? ''}
+				/>
+			{:else}
+				<input
+					id="{idPrefix}-{field.name}"
+					type={field.name.toLowerCase().includes('password') || field.name.toLowerCase().includes('secret') ? 'password' : 'text'}
+					value={values[field.name] ?? ''}
+					oninput={(e) => onchange(field.name, e.currentTarget.value)}
+					class={inputClass}
+					placeholder={field.description ?? field.label}
+				/>
+			{/if}
+		</div>
+	{/each}
+</div>