Remove or repair stale CallToAction component

[plx]

Summary

CallToAction.astro appears to be unused and currently references a missing SCSS path (../assets/scss/base/mixins), so it fails if imported.

Affected file:

• src/components/CallToAction.astro

Why This Matters

Dead or broken components increase maintenance noise and create future integration failure risk.

Proposed Strategy

Choose one:

1. Remove component if not needed.
2. Or make it compile in current stack:

• Replace missing SCSS dependency with existing styling approach (Tailwind/global CSS), and
• Add a usage or test to ensure it stays functional.

Done Criteria / Validation

• Component is either removed or builds successfully when imported.
• No unresolved imports remain.
• npm run build passes.
• If retained, include at least one usage path covered by npm run qa.