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

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

frontend/src/components/home/HeroSection.tsx

@@ -72,7 +72,7 @@ export function HeroSection({ onOpenDemoModal }: HeroSectionProps) {
             animate={{ opacity: 1, y: 0 }}
             transition={{ duration: 0.5, delay: 0.2 }}
           >
-            Opinionated, secure, and production-ready. PragmaStack gives you the solid foundation
+            Opinionated, secure, and production-ready. Syndarix gives you the solid foundation
             you need to stop configuring and start shipping.{' '}
             <span className="text-foreground font-medium">Start building features on day one.</span>
           </motion.p>
@@ -93,7 +93,7 @@ export function HeroSection({ onOpenDemoModal }: HeroSectionProps) {
             </Button>
             <Button asChild size="lg" variant="outline" 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"
               >