docs(ts-sdk): document how to build, publish, edit

Author: cor

ts-sdk/README.md

@@ -0,0 +1,27 @@
+# Union TypeScript SDK
+
+`@unionlabs/sdk`
+
+## How to build and test
+
+```sh
+nix build .#ts-sdk -L
+```
+
+## How to publish
+
+
+First, bump `version` in `package.json`. Then:
+
+```sh
+nix run .#publish-ts-sdk -L
+```
+
+## How to develop
+
+```sh
+nix develop
+cd ts-sdk/
+npm install
+npm run test-watch
+```