Resolves the system identity mismatch between the Linux username (worsch)
and the bootstrap identity (tegwick / Bernd Worsch / custom email).
Resolution order for all three fields: flag > config > system derivation.
Config is updated on every init so --force reinits are idempotent without
repeating the flags.
- cli.py: extract _resolve_init_params(); add --username / --fullname args;
persist all three fields to config.yaml on init
- tests/test_cli.py: 13 new tests covering flag priority, config fallback,
system derivation, config persistence, idempotent --force reinit
54 tests passing.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
