Read nbdev-test cell timeout and timing threshold, and nbdev-create-config identity fields, from user config

[jph00]

nbdev-test's cell_timeout and cell_timing_min now default to the config keys of the same name, so a preferred bound can live in ~/.config/nbdev/config.toml or a project's [tool.nbdev] table instead of being repeated on every run. cell_timeout joins nbdev_defaults at 600, and the flags still override per run.

nbdev-create-config falls back to user, author, and author_email from the user config when neither the arguments nor the git remote supply them, so nbdev-new no longer needs --user on a machine with a config file. The user-config section of the config page now lists what the file can hold.

The skill's test instruction drops its hard-coded flags in favour of the bare command.

https://claude.ai/code/session_019kQ64967EEsdUQuzNU2mML