DISCO-142: Print Only SDK Token to Stdout - #450

Description

content-cli sdk token is meant to be captured in scripts, e.g. CELONIS_TOKEN=$(content-cli sdk token) npm install …. The banner and the beta notice were printed to stdout too, and -q only suppresses the banner. So the captured value wasn't a valid token and npm rejected it as an HTTP header. Diagnostics now go to stderr, so stdout carries only the command's output.

• The banner is printed to stderr.
• The console logger writes warn and error to stderr. This applies to every command, and keeps errors out of captured output.
• Beta notices for commands and options are logged as warn, so they go to stderr together with the deprecation notice.
• The sdk token docs no longer need -q. They show the app-scoped registry URL /api/codespace/apps/<appId>/npm/ with an .npmrc that reads the token from CELONIS_TOKEN.

Relevant links

• Jira: https://celonis.atlassian.net/browse/DISCO-142