Introduce FORMA branding, automated checks and portfolio showcase

[SakuraUltra]

The storefront now presents a cohesive FORMA boutique identity across discovery, product selection, cart, demo checkout and saved orders. The warm ivory/olive palette, editorial home page and responsive layouts preserve the existing guest shopping flow and make the repository useful as both a portfolio piece and an MIT-licensed template.

• Activate GitHub Actions for pull requests and main: locked dependency installation, lint, commerce/checkout tests and production build with read-only permissions.
• Add a brand icon and generated social preview; retain configurable store naming, light/dark themes, keyboard search and mobile filters.
• Add desktop/mobile/order screenshots, a 32-second walkthrough assembled from actual UI captures, and bilingual project/CV notes.

Validation: local lint, 27 tests and production build passed. Browser checks covered desktop and 390px mobile layouts, light/dark themes, category filters, mobile search/navigation, variant selection, cart recovery after reload, simulated checkout, order recovery and delivery advancement. Browser console reported no errors in the final walkthrough.

This remains a browser-local commerce demo: no real charges, accounts or shipments. Public hosting restoration is outside this change.