feat: add Node.js and Python SDKs

- Node.js SDK: TypeScript, ESM+CJS, zero deps (uses native fetch)
- Python SDK: zero deps (uses urllib), Python 3.8+
- Both fully documented with examples and type hints
- Ready for npm/PyPI publishing

sdk/node/tsconfig.json

@@ -0,0 +1,14 @@
+{
+  "compilerOptions": {
+    "target": "ES2022",
+    "module": "ESNext",
+    "moduleResolution": "node",
+    "declaration": true,
+    "outDir": "./dist",
+    "rootDir": "./src",
+    "strict": true,
+    "esModuleInterop": true,
+    "skipLibCheck": true
+  },
+  "include": ["src"]
+}