feat: scaffold Svelte app with shared types and scale calculation

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

tsconfig.json

@@ -0,0 +1,16 @@
+{
+  "extends": "@tsconfig/svelte/tsconfig.json",
+  "compilerOptions": {
+    "target": "ES2022",
+    "module": "ESNext",
+    "moduleResolution": "bundler",
+    "lib": ["ES2022", "DOM", "DOM.Iterable"],
+    "types": ["node"],
+    "strict": true,
+    "noEmit": true,
+    "verbatimModuleSyntax": true,
+    "isolatedModules": true,
+    "skipLibCheck": true
+  },
+  "include": ["src/**/*.ts", "src/**/*.svelte", "tests/**/*.ts", "vite.config.ts"]
+}