Preserve `click.secho()` formatting for plain log output

[ephur]

Ensure that log output remains colorized and styled via click when --log-format is not set to JSON. Avoid breaking current terminal output behavior.

[ephur]

🤖 Initial triage (AI-generated):

This issue ensures that click.secho() continues to format logs (color, bold) in plain mode. Once log_format is introduced (see #106), log() should conditionally:

• Use click.secho() for plain
• Use print(json.dumps(...)) for JSON

No change needed to log_level filtering — just preserve terminal experience.

🧪 Check for output changes when piping to files or CI logs.

Disclaimer: This triage is AI-generated and may need refinement.