refactor(theme): remove dynamic styling systems and migrate to static CSS architecture

This commit introduces a major internal refactor of the theme, replacing all
dynamic styling mechanisms with a fully static, CSS-based system.

The previous implementation relied on WordPress Customizer settings, PHP-based
style generation, and inline CSS injection for fonts, colors, and header behavior.
These systems have been completely removed and replaced with a deterministic
architecture using CSS variables and dedicated stylesheets.

Key changes:
- Removed dynamic font system (Google/local/inline CSS)
- Removed dynamic color system and Customizer controls
- Removed legacy compatibility layer (legacy-aliases.php)
- Removed custom header support and related UI (header image, text color)
- Eliminated inline <style> injection in wp_head
- Introduced static typography system via fonts.css
- Introduced static color system via colors.css
- Refactored style.css to rely entirely on CSS variables
- Cleaned up conflicting font declarations and redundant rules
- Simplified theme structure and reduced PHP overhead
- Aligned translation template with theme slug (zeitfresser.pot)

Result:
- Improved frontend performance and caching behavior
- Reduced PHP execution and complexity
- Fully deterministic rendering without runtime style mutations
- Cleaner, more maintainable codebase

No visual changes intended.

inc/blocks/blocks.php

@@ -15,9 +15,6 @@ require dirname( __FILE__ ) . '/includes/sanitize.php';
 require dirname( __FILE__ ) . '/includes/register-controls.php';
 
 require dirname( __FILE__ ) . '/site-identity/site-identity.php';
-require dirname( __FILE__ ) . '/colors/colors.php';
-require dirname( __FILE__ ) . '/font-family/font-family.php';
-require dirname( __FILE__ ) . '/font-customization/font-customization.php';
 require dirname( __FILE__ ) . '/general/general.php';
 require dirname( __FILE__ ) . '/post-detail/post-detail.php';
 require dirname( __FILE__ ) . '/footer-copyright/footer-copyright.php';