feat: V1 prototype — Vite/React/TS tileset generator

- Scaffold: package.json, tsconfig.json, vite.config.ts, index.html
- src/lib/imageProcessor.ts: full pipeline (normalize, offset, seam repair, export, validation)
- src/components/UploadPanel.tsx: drag-and-drop, file picker, clipboard paste
- src/components/SettingsPanel.tsx: all controls per spec
- src/components/PreviewPanel.tsx: Original / Tileable / Repeated tabs
- src/components/ErrorBanner.tsx: dismissible error/warning banners
- src/App.tsx: root component wiring everything together
- src/index.css: dark premium glassmorphism theme w/ Inter font

node_modules/postcss/README.md

@@ -0,0 +1,28 @@
+# PostCSS
+
+<img align="right" width="95" height="95"
+     alt="Philosopher’s stone, logo of PostCSS"
+     src="https://postcss.org/logo.svg">
+
+PostCSS is a tool for transforming styles with JS plugins.
+These plugins can lint your CSS, support variables and mixins,
+transpile future CSS syntax, inline images, and more.
+
+PostCSS is used by industry leaders including Wikipedia, Twitter, Alibaba,
+and JetBrains. The [Autoprefixer] and [Stylelint] PostCSS plugins are some of the most popular CSS tools.
+
+---
+
+<img src="https://cdn.evilmartians.com/badges/logo-no-label.svg" alt="" width="22" height="16" />  Built by
+<b><a href="https://evilmartians.com/devtools?utm_source=postcss&utm_campaign=devtools-button&utm_medium=github">Evil Martians</a></b>, go-to agency for <b>developer tools</b>.
+
+---
+
+[Abstract Syntax Tree]: https://en.wikipedia.org/wiki/Abstract_syntax_tree
+[Evil Martians]: https://evilmartians.com/?utm_source=postcss
+[Autoprefixer]: https://github.com/postcss/autoprefixer
+[Stylelint]: https://stylelint.io/
+[plugins]: https://github.com/postcss/postcss#plugins
+
+## Docs
+Read full docs **[here](https://postcss.org/)**.