feat(min): min with no args prints the help text - #1089

Change bare min with no subcommand to print help and exit

Previously, running min with no arguments would attempt to resolve and attach to a session (or activate a new one). It now prints the top-level CLI help and exits successfully without starting the daemon or creating sessions.

• cmd_default in lib.rs is replaced with a synchronous function that calls clap::CommandFactory to print help.
• The ensure_activate_on_empty_allowed guard and related session-resolution logic are removed from the default path.
• Users should use min session attach or min session activate for the previous behavior.
• Behavioral Change: bare min no longer starts the daemon or attaches to a session; existing scripts relying on that behavior will need to be updated.

^{Macroscope summarized 25aa096.}

Summary by CodeRabbit

• Behavior Changes

  • Running min without a subcommand now displays top-level help and exits successfully.
  • Bare min no longer contacts the daemon, activates sessions, or attaches to existing sessions.
  • Use explicit session commands to activate or attach to a session.

• Documentation

  • Updated CLI reference documentation to reflect the new default behavior and command guidance.