AI-131 add members mutation commands

[thebiglabasky]

Summary

• Add checkly members update <member> --role <role> for public account member role updates.
• Add checkly members delete <member> for public account member removal.
• Let <member> be either an email address or user ID. Email-like values are resolved through the account-scoped members list with an exact active-member email match; --email and --id force interpretation when needed.
• Keep the existing checkly account members ... spelling as hidden compatibility aliases.
• Route both mutations through the existing confirmation wrapper with --force and --dry-run, so agent/CI mode refuses to execute without explicit confirmation.
• Extend account-member REST client types, command metadata coverage, root help topic metadata, pagination hints, and AI-context docs.

Dependency

Depends on checkly/monorepo#2053 for the public PATCH and DELETE account member endpoints.

Backend model note

Checked the monorepo schema: memberships is unique on (userId, accountId), while there is no (accountId, email) membership uniqueness constraint. The CLI therefore resolves email by exact active-member email match from the current account's public list response, then calls the userId mutation endpoint.

Validation

• pnpm install (completed; emitted the expected simple-git-hooks warning for Codex worktree .git file)
• pnpm --filter checkly run clean:dist && pnpm --filter checkly run prepare:dist && pnpm --filter checkly run prepack
• pnpm exec eslint packages/cli/src/helpers/account-member-target.ts packages/cli/src/rest/account-members.ts packages/cli/src/commands/members.ts packages/cli/src/commands/members/update.ts packages/cli/src/commands/members/delete.ts packages/cli/src/commands/__tests__/account-members.spec.ts packages/cli/src/commands/__tests__/account-members-mutations.spec.ts packages/cli/src/commands/__tests__/command-metadata.spec.ts packages/cli/src/formatters/account-members.ts packages/cli/src/ai-context/context.ts
• pnpm exec vitest --run src/commands/__tests__/account-members.spec.ts src/commands/__tests__/account-members-mutations.spec.ts src/commands/__tests__/command-metadata.spec.ts src/formatters/__tests__/account-members.spec.ts
• Manual help checks for checkly members update, checkly members delete, and the legacy checkly account members ... alias.