fix: Replace Lato with Sailic and Inter fonts (#660)

[jose-blockchain]

Description:

Problem:
The website was using the Lato font throughout, but the brand guidelines specify that Sailic should be used for larger text/headings and Inter should be used for body text. This inconsistency with the brand identity needed to be corrected (issue #660).

Solution:

• Replaced all instances of Lato font with the correct brand fonts:
  • Inter for body text, smaller text elements, and general content
  • Sailic for larger text, headings (h4), and prominent display text
• Updated Google Fonts import in base.html to load Sailic and Inter
• Added sans-serif fallbacks to all font declarations to ensure graceful degradation if fonts fail to load
• Updated 31 files total including:
  • CSS files (main stylesheet, page-specific, and component styles)
  • HTML templates
  • Email templates (with proper fallbacks for email client compatibility)
  • SVG files (with appropriate font assignments based on text size)

Why this solution is better:

• Aligns the website with brand guidelines
• Maintains visual consistency across all pages
• Includes proper fallbacks to prevent UI breakage
• Email templates remain compatible with clients that don't support web fonts
• No breaking changes - fonts are swapped with equivalent weights and styles

Checklist:

• Test your work and double-check to confirm that you didn't break anything
  • Verified all Lato references removed (except in text content like "regulatory")
  • Confirmed all font declarations include proper sans-serif fallbacks
  • Checked Google Fonts URL formatting is correct
  • Verified email template compatibility with fallback fonts
  • Tested that fonts load correctly and fallbacks work as expected
• Update the README, if necessary
  • No README updates needed - this is a styling change that doesn't affect setup or usage
• Run translation commands if any strings are changed
  • No translatable strings were changed - only font-family CSS declarations and font imports were modified

Related Issue

Closes #660

[jose-blockchain]

please review @DanielVF @nick @ryana @andrewhyde @matt-bullock if still needed.