♻️ refactor: remove duplicated code (Quick Wins)

- Delete unused Input.svelte from Picture app (70 LOC)
- Remove sleep() from shared-api-client, import from shared-utils
- Fix NodeJS.Timeout type for browser compatibility

Part of consolidation effort - see docs/CONSOLIDATION_OPPORTUNITIES.md

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

packages/shared-utils/src/async.ts

@@ -51,7 +51,7 @@ export function debounce<T extends (...args: any[]) => any>(
 	fn: T,
 	delay: number
 ): (...args: Parameters<T>) => void {
-	let timeoutId: NodeJS.Timeout | null = null;
+	let timeoutId: ReturnType<typeof setTimeout> | null = null;
 
 	return (...args: Parameters<T>) => {
 		if (timeoutId) {