docs(readme): escape table command pipes

[zikolach]

Summary

• escape pipe characters inside inline command examples in README tables
• verified markdown table column counts across markdown files

Validation

• custom markdown table scan: no unescaped pipe characters inside inline code spans in markdown table rows
• custom markdown table scan: table column counts look consistent

Docs-only change; skipped typecheck/test.

[Copilot]

Pull request overview

This docs-only PR fixes README table rendering by escaping pipe characters inside inline command examples.

Changes:

• Escapes messenger option separators in local /relay command examples.
• Escapes alias option separators in remote command examples.