Add strict TypeScript config with @/ and @phase0/ aliases

src/typecheck-placeholder.ts

@@ -0,0 +1 @@
+export {};

tsconfig.json

@@ -0,0 +1,30 @@
+{
+  "compilerOptions": {
+    "target": "ES2023",
+    "module": "ESNext",
+    "moduleResolution": "Bundler",
+    "lib": ["ES2023", "DOM", "DOM.Iterable"],
+    "jsx": "react-jsx",
+    "strict": true,
+    "noUncheckedIndexedAccess": true,
+    "noImplicitOverride": true,
+    "noFallthroughCasesInSwitch": true,
+    "exactOptionalPropertyTypes": true,
+    "isolatedModules": true,
+    "verbatimModuleSyntax": true,
+    "resolveJsonModule": true,
+    "allowSyntheticDefaultImports": true,
+    "esModuleInterop": true,
+    "skipLibCheck": true,
+    "noEmit": true,
+    "forceConsistentCasingInFileNames": true,
+    "baseUrl": ".",
+    "paths": {
+      "@/*": ["src/*"],
+      "@phase0/*": ["scripts/phase-0/*"]
+    },
+    "types": ["node", "vitest/globals"]
+  },
+  "include": ["src/**/*.ts", "src/**/*.tsx", "vitest.config.ts"],
+  "exclude": ["node_modules", "dist", "ClientApp", "wwwroot"]
+}