Hunter Bown
4369410df7
fix(auth): show credential source table
## Summary
- show config, keyring, and env credential sources in deepseek auth status
- point env-only auth failures at auth status and auth set recovery commands
- document auth status and provider key precedence
## Test plan
- cargo test -p deepseek-tui-cli auth_ --locked
- cargo test -p deepseek-tui-cli --locked
- cargo test -p deepseek-tui env_only_auth_error_gets_recovery_hint --locked
- cargo test -p deepseek-config api_key --locked
- cargo test -p deepseek-config config_file_resolves_above_env_and_keyring --locked
- cargo test -p deepseek-config keyring_resolves_when_config_file_empty_even_if_env_is_set --locked
- cargo test -p deepseek-secrets --locked
- cargo fmt --all -- --check
- git diff --check
- cargo clippy -p deepseek-tui-cli -p deepseek-tui -p deepseek-secrets --all-targets --all-features --locked -- -D warnings
Closes #907