`rtk init -g` shows redundant "run `rtk init -g`" warning

Description

Running rtk init -g prints a confusing warning before it has a chance to install the hook:

$ rtk init -g
[rtk] /!\ No hook installed — run `rtk init -g` for automatic token savings

The warning tells the user to run the exact command they're already running.

Steps to Reproduce

1. Uninstall any existing hooks: rtk init -g --uninstall
2. Reset the rate-limit marker: rm ~/Library/Application\ Support/rtk/.hook_warn_last
3. Run rtk init -g
4. Observe the redundant warning before the hook is installed

Root Cause

maybe_warn() in hook_check.rs fires for all commands except Gain before the command dispatches. When the command is Init, the hook hasn't been installed yet, so the check sees a missing hook and warns.

The warning is also rate-limited to once per day, making it hard to reproduce consistently.

Expected Behavior

rtk init -g should not warn missing hooks nor redundantly recommend running rtk init -g again. If anything, it should indicate that it's about to install the hooks.