kpt: Build e-commerce example kpt package

Currently, while kpt is a highly capable tool for declarative Kubernetes management, its official examples rely heavily on complex, specialized domains like telecommunications. This creates a high barrier to entry for standard developers trying to learn the "configuration-as-data" approach. This project solves that problem by providing a universally understood example. I will package the popular "Online Boutique" (or a similar application) microservices application into a complete, modular kpt package. Using this baseline, I will build and thoroughly document four practical customization workflows: Changing the store theme (e.g., adapting the boutique into a florist or car accessory site). Localizing language and currency settings. Configuring regional Sales Tax and VAT. Adjusting deployment configurations for Small, Medium, and Large scales. etc.. Ultimately, this project is an opportunity for me to deeply learn and demonstrate how kpt handles complex mutations without relying on traditional templating tools like Helm. The final deliverable will be a production-grade package contributed directly to the CNCF kpt toolchain, making the platform significantly more accessible to new users in the open-source community.