Add debugging section to new kernel docs

[blink1073]

Summary

• Adds a Debugging section to docs/new_kernel.md
• Documents jupyter console --log-level=debug --kernel=<name> for inspecting ZMQ messages during kernel development
• Includes a note to install jupyter-console via pip if not already present

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 90.95%. Comparing base (c9e48e8) to head (5834ff0).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #362   +/-   ##
=======================================
  Coverage   90.95%   90.95%           
=======================================
  Files          51       51           
  Lines        2874     2874           
  Branches      402      402           
=======================================
  Hits         2614     2614           
  Misses        181      181           
  Partials       79       79           

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