feat(phase2): phase 6 - integration & polish

Fix all build/type/lint errors, write 60 new tests (175 total),
update seed with new widget types and team board permissions,
install missing svelte-i18n dependency, fix DynamicIcon for Svelte 5.

src/lib/components/ui/DynamicIcon.svelte

@@ -18,10 +18,11 @@
 	}
 
 	const iconComponent = $derived(
-		name ? (icons as Record<string, unknown>)[toPascalCase(name)] ?? null : null
+		name ? ((icons as Record<string, unknown>)[toPascalCase(name)] as typeof import('svelte').SvelteComponent | undefined) ?? null : null
 	);
 </script>
 
 {#if iconComponent}
-	<svelte:component this={iconComponent} {size} class={className} />
+	{@const Icon = iconComponent}
+	<Icon {size} class={className} />
 {/if}