Fix SEO inconsistencies: founding year, accuracy rates, sitemap, alt text

- Fix founding year from 2018 to 2015 across about.php, organization-schema.php, and index.php schema
- Standardise data accuracy rate to 99.8% across about.php and services/web-scraping.php (was 99.7%/99.9%)
- Remove google-oauth-callback from sitemap.xml
- Fix UK Gambling Commission logo alt text (remove misleading 'regulatory compliance' label)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

services/web-scraping.php

@@ -594,7 +594,7 @@ $breadcrumbs = [
                     <span class="stat-label">Projects Delivered</span>
                 </div>
                 <div class="stat">
-                    <span class="stat-number">99.7%</span>
+                    <span class="stat-number">99.8%</span>
                     <span class="stat-label">Data Accuracy</span>
                 </div>
                 <div class="stat">
@@ -669,7 +669,7 @@ $breadcrumbs = [
                     <p>From simple static pages to complex JavaScript applications, we handle all website technologies. Extract from one site or thousands simultaneously with our scalable infrastructure.</p>
                 </div>
                 <div class="feature-card">
-                    <h3>99.7% Data Accuracy</h3>
+                    <h3>99.8% Data Accuracy</h3>
                     <p>Multi-layer validation, automated quality checks, and human review processes ensure the data you receive is accurate, complete, and properly formatted.</p>
                 </div>
                 <div class="feature-card">