Feat: Add economical readme with usage examples

readme.md

@@ -1 +1,41 @@
-NPM Package
+# ZWUS
+
+Zero Width Unicode Steganography — hide text inside invisible characters.
+
+`npm i zwus`
+
+## Usage
+
+```js
+import zwus from 'zwus';
+
+// Encode & decode strings
+const hidden = zwus.encodeString("secret");
+const revealed = zwus.decodeToString(hidden);
+// "secret"
+
+// Encode & decode number arrays
+const encoded = zwus.encodeNumberArray([72, 101, 108]);
+const decoded = zwus.decodeToNumberArray(encoded);
+// [72, 101, 108]
+```
+
+### Base
+
+Higher base = shorter output, but more likely visible in some renderers.
+
+```js
+zwus.encodeString("hi", 3)  // default, safest
+zwus.encodeString("hi", 6)  // compact
+zwus.encodeString("hi", 8)  // most compact
+```
+
+Decode must match the encode base:
+
+```js
+zwus.decodeToString(encoded, 6)
+```
+
+## License
+
+[WTFPL](license)