feat: initialize FewLineSDK project with TypeScript setup

- Add package.json with dependencies and scripts for building and linting
- Create initial FewLineSDK class in src/index.ts
- Set up TypeScript configuration in tsconfig.json

tsconfig.json

@@ -0,0 +1,14 @@
+{
+  "compilerOptions": {
+    "target": "ES2020",
+    "module": "CommonJS",
+    "declaration": true,
+    "outDir": "dist",
+    "strict": true,
+    "esModuleInterop": true,
+    "skipLibCheck": true,
+    "forceConsistentCasingInFileNames": true
+  },
+  "include": ["src"],
+  "exclude": ["node_modules", "dist", "**/*.test.ts"]
+}