feat(cli): add --yes flag to onboard for non-interactive quickstart

Skip the setup path prompt and auto-start the server when --yes is
passed, enabling fully non-interactive onboarding with local defaults.
Opens the browser automatically on server listen.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

docs/cli/setup-commands.md

@@ -44,6 +44,12 @@ Start immediately after onboarding:
 pnpm paperclipai onboard --run
 ```
 
+Non-interactive defaults + immediate start (opens browser on server listen):
+
+```sh
+pnpm paperclipai onboard --yes
+```
+
 ## `paperclipai doctor`
 
 Health checks with optional auto-repair: