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/update-browserslist-db/check-npm-version.js

@@ -0,0 +1,17 @@
+let { execSync } = require('child_process')
+let pico = require('picocolors')
+
+try {
+  let version = parseInt(execSync('npm -v'))
+  if (version <= 6) {
+    process.stderr.write(
+      pico.red(
+        'Update npm or call ' +
+          pico.yellow('npx browserslist@latest --update-db') +
+          '\n'
+      )
+    )
+    process.exit(1)
+  }
+  // eslint-disable-next-line no-unused-vars
+} catch (e) {}