docs(coding-agent): add uninstall instructions

packages/coding-agent/docs/quickstart.md

@@ -10,6 +10,26 @@ Pi is distributed as an npm package:
 npm install -g @earendil-works/pi-coding-agent
 ```
 
+### Uninstall
+
+Use the package manager that installed pi. The curl installer uses npm globally, so curl and npm installs are removed with npm:
+
+```bash
+# curl installer or npm install -g
+npm uninstall -g @earendil-works/pi-coding-agent
+
+# pnpm
+pnpm remove -g @earendil-works/pi-coding-agent
+
+# Yarn
+yarn global remove @earendil-works/pi-coding-agent
+
+# Bun
+bun uninstall -g @earendil-works/pi-coding-agent
+```
+
+Uninstalling pi leaves settings, credentials, sessions, and installed pi packages in `~/.pi/agent/`.
+
 Then start pi in the project directory you want it to work on:
 
 ```bash