fix(cli): use --name flag in gateway destroy hint messages

[drew]

Summary

Fix invalid gateway destroy commands in error hint messages. The --name flag was missing, causing the gateway name to be treated as an unexpected positional argument.

Related Issue

N/A — discovered by running the suggested command from the "gateway not reachable" error message.

Changes

• Added --name flag to all openshell gateway destroy hint messages across openshell-bootstrap and openshell-cli
• Affected 8 hint messages in 3 files: errors.rs (7), lib.rs (1), run.rs (1)

Testing

• mise run pre-commit passes
• Unit tests added/updated
• E2E tests added/updated (if applicable)

Checklist

• Follows Conventional Commits
• Commits are signed off (DCO)
• Architecture docs updated (if applicable)

[github-actions]

All contributors have signed the DCO ✍️ ✅
_{Posted by the DCO Assistant Lite bot.}