Fix navbar across all pages: add nav include, fonts, active state, spacing, stats, error pages

- Add nav.php include to 5 missing pages (cost-calculator, thank-you, 403, 404, 500)
- Add ErrorDocument directives to .htaccess for custom 403/404/500 pages
- Fix bogus accuracy stats (homepage, web-scraping, location pages)
- Fix invisible CTA buttons on property and financial service pages
- Add Google Fonts (Roboto Slab + Lato) to all pages missing it (tools, blog articles, error pages)
- Add active nav link highlighting (teal underline for current page)
- Improve footer contrast to WCAG AA, equal-height cards, mobile text scaling
- Consistent navbar-to-content spacing across all pages
- Bump cache version to v1.1.3

quote.php

@@ -193,7 +193,7 @@ $breadcrumbs = [
     
     <style>
         .quote-hero {
-            padding: 100px 0 30px;
+            padding: 100px 0 30px; /* padding-top overridden by main.css */
             background: linear-gradient(135deg, #f5f7fa 0%, #c3cfe2 100%);
             text-align: center;
         }