Problem

When users run sentry issue explain or sentry issue plan on an org without Seer enabled or with insufficient billing, they get unhelpful error messages:

• 402: "No budget for Seer Autofix. Check your billing plan."
• 403: "Seer Autofix is not enabled for this organization."

These errors don't tell users where to go to fix the problem.

Solution

Add a SeerError class that provides:

• Clear explanation of the problem
• Actionable suggestions with direct URLs to billing/settings pages
• Proper formatting following the CliError pattern

Example output:

Seer requires a paid plan.

To use Seer features, upgrade your plan:
  https://my-org.sentry.io/settings/billing/