fix(install): register local gateway before probing listener

[drew]

Summary

Move local gateway registration before the install script listener probe so fresh Homebrew and systemd installs import the package-managed mTLS bundle before the probe needs it.

Related Issue

None.

Changes

• Register the local gateway immediately after starting the package-managed service.
• Run the mTLS listener probe after registration so gateway add --local has created the CLI mTLS bundle.

Testing

• mise run pre-commit passes
• Unit tests added/updated (not applicable: installer ordering only)
• E2E tests added/updated (not applicable)
• sh -n install-dev.sh passes

Checklist

• Follows Conventional Commits
• Commits are signed off (DCO)
• Architecture docs updated (not applicable: installer script only)