feat: complete Syndarix rebranding from PragmaStack

- Update PROJECT_NAME to Syndarix in backend config
- Update all frontend components with Syndarix branding
- Replace all GitHub URLs with Gitea Syndarix repo URLs
- Update metadata, headers, footers with new branding
- Update tests to match new URLs
- Update E2E tests for new repo references
- Preserve "Built on PragmaStack" attribution in docs

Closes #13

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Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

frontend/src/components/home/CTASection.tsx

@@ -49,7 +49,7 @@ export function CTASection({ onOpenDemoModal }: CTASectionProps) {
           <div className="flex flex-col sm:flex-row items-center justify-center gap-4 pt-4">
             <Button asChild size="lg" className="gap-2 text-base group">
               <a
-                href="https://github.com/your-org/fast-next-template"
+                href="https://gitea.pragmazest.com/cardosofelipe/syndarix"
                 target="_blank"
                 rel="noopener noreferrer"
               >
@@ -75,7 +75,7 @@ export function CTASection({ onOpenDemoModal }: CTASectionProps) {
             </Button>
             <Button asChild size="lg" variant="ghost" className="gap-2 text-base group">
               <a
-                href="https://github.com/your-org/fast-next-template#documentation"
+                href="https://gitea.pragmazest.com/cardosofelipe/syndarix#documentation"
                 target="_blank"
                 rel="noopener noreferrer"
               >