Improve onboarding

[stefanbuck]

Hi,

I really love the idea of ckp. I do rely on aliases and my terminal history a lot to re-run commands which is kind of working but not always.

After installing the ckp I was confronted with a weird error. Turns out I did not follow the setup instructions, in particular, I did not run ckp init.

I'm pretty sure I'm not the only one that skims the instructions. How about adding a setup validation step that runs on every command and prints a hint if the initialization step is missing.

Current behaviour

ckp add code 'echo hello'
Error: failed to pull remote changes: failed to fetch origin/main: chdir /Users/stefan/.ckp/repo: no such file or directory:

Expected behaviour

ckp add code 'echo hello'

Warning: The ckp storage repository is missing. Please run `ckp init` to complete the setup.

Looking forward to see how this project evolves, great work so far.