`skills install --registry` help example is misleading about argument handling

[cornjosh]

The help text for picoclaw skills install --registry is confusing and doesn't accurately reflect how the command works.

Current Help Text:

Example:
  picoclaw skills install sipeed/picoclaw-skills/weather
  picoclaw skills install --registry clawhub github

And the flag description:

--registry string   Install from registry: --registry <name> <slug>

Problem:

The example picoclaw skills install --registry clawhub github suggests that:

• --registry clawhub specifies the registry name
• github is the slug

However, looking at the actual implementation in cmd/picoclaw/internal/skills/install.go:

if registry != "" {
    return skillsInstallFromRegistry(cfg, args[0], args[1])
}

The --registry flag value is only used as a switch to enable registry mode. The actual registry name and slug both come from positional arguments (args[0] and args[1]).

This means:

• The flag description --registry <name> <slug> is misleading
• Users might expect the flag value to be used, but it's not

Suggested Fix:

Either:

1. Update the implementation to use the flag value as the registry name (preferred, more intuitive CLI)
2. Or update the help text to accurately reflect that both registry name and slug are positional arguments

[harshbansal7]

Apologies for this, probably missed it in #332 due to a lot of comments.
Thanks for the fix.