Encode Intelligent Mail Barcodes (IMB) for USPS
npm install imb-encodeA Node.js port of the USPS Intelligent Mail Barcode (IMB) encoder,
replicating much of the logic from the original usps4cb.c code.
Exports a function encodeIMB(trackingString, routingString) that returns
a 65-character string containing 'A', 'D', 'F', 'T' representing the
full IMB (4-state) barcode.
```bash
npm install imb-encode