Startup config mistakes were handled inconsistently: an identity collision
exited cleanly, but a missing or invalid config file (FileNotFoundError /
RuntimeError from load_config) and a missing identity key (RuntimeError) dumped
a full traceback -- and load_config ran outside main()'s try, so those errors
escaped the fatal handler entirely.
Add repeater/exceptions.py with ConfigurationError(RuntimeError) and re-parent
IdentityConfigurationError onto it (it stays a RuntimeError, so existing
except-sites are unaffected). Raise ConfigurationError for the missing/invalid
config file, the config-load failure, and the missing identity key. Move
load_config and daemon construction inside main()'s try and catch
ConfigurationError there, logging just the message and exiting 1; unexpected
failures still log with a traceback.
agessaman