docs: troubleshooting guide for the laptop install

[huang195]

Feature Description

What actually goes wrong with a laptop install has no page.

Proposed Solution

• CA not trusted: how to tell, how to fix
• Port 47600 already in use
• Service will not start, or starts and dies — launchd and systemd
• Another tool broke — cross-reference the tool-compatibility issues (feature: git, gh and ssh keep working with Cortex running #946, feature: language toolchains and scripted HTTPS clients keep working #947)
• No events appearing though the agent is running
• Numbers look wrong or missing
• Where the logs are, and what to attach to a bug report

Additional Context

Part of the Cortex v0.9.0 release.