E20: config file and profiles, --profile currently selects from nothing

[tamnd]

Spec: notes/Spec/2115/07-enhancements.md, item E20.

Problem

ConfigDir() exists, config is a command, and kit gives us a --profile global. Nothing reads a config file, so --profile selects from an empty set. All configuration is flags and environment variables.

What to do

• Read ~/.config/ccrawl/config.toml with a [default] section plus named profiles, overriding endpoints, timeouts, workers, library dir, HF repo and global rate.
• Precedence is flag, then env, then profile, then default.
• Make config show print the resolved value and where it came from.

Done when

• ccrawl --profile bulk search ... picks up the profile settings
• config show attributes every value to flag, env, profile or default

Estimate: 1 day.