Adds some posts and cleanups

[pftg]

Summary by CodeRabbit

• New Features

  • Added CTA shortcode for pages.
  • Introduced CSS utility classes.
  • Published a downloadable Developer Performance Scorecard lead magnet.
  • Added Emergency CTO service page.

• Documentation

  • Added extensive CSS architecture/migration guides (BEM/semantic, utilities, component hierarchy).
  • Published multiple in-depth blog posts on Rails architecture, performance, upgrades, testing, Ruby memory, and management for non-technical founders.
  • Updated content writing guidelines and governance docs.

• Tests

  • Refactored test harness/base class and dynamic port handling; improved Hugo test server middleware.

• Chores

  • Added unit-test GitHub Actions workflow.
  • Updated .gitignore (ignore _tmp/).