Groceed - Completely refreshed interface, more fast and stable

We refreshed the interface following Material Design 3 (Expressive), focusing on better clarity and visual hierarchy. Under the hood, the entire codebase has been refactored to fully embrace SvelteKit and is now running on Cloudflare Workers. We also migrated from MongoDB to Cloudflare D1. The result is a dramatic performance boost—everything feels noticeably faster.