Fix : Add --log-path argument parsing to fdctl

[tanmay4l]

Fixes the "unknown argument" error when using fdctl --log-path.

Changes:

• Add --log-path parsing in fd_main() using fd_env_strip_cmdline_cstr()
• Pass opt_log_path to fd_main_init() following same pattern as --config
• Update help text to document --log-path option

Testing:

• Follows exact same pattern as existing --config argument parsing
• No breaking changes to existing functionality

Resolves #6222

[tanmay4l]

@kbhargava-jump can u review this pr if possible