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/Header.tsx

@@ -48,13 +48,13 @@ export function Header({ onOpenDemoModal }: HeaderProps) {
           >
             <Image
               src="/logo-icon.svg"
-              alt="PragmaStack Logo"
+              alt="Syndarix Logo"
               width={32}
               height={32}
               className="h-8 w-8"
             />
             <span className="bg-gradient-to-r from-primary to-primary/60 bg-clip-text text-transparent">
-              PragmaStack
+              Syndarix
             </span>
           </Link>
 
@@ -72,7 +72,7 @@ export function Header({ onOpenDemoModal }: HeaderProps) {
 
             {/* GitHub Link with Star */}
             <a
-              href="https://github.com/your-org/fast-next-template"
+              href="https://gitea.pragmazest.com/cardosofelipe/syndarix"
               target="_blank"
               rel="noopener noreferrer"
               className="flex items-center gap-2 text-sm font-medium text-muted-foreground hover:text-foreground transition-colors"
@@ -135,7 +135,7 @@ export function Header({ onOpenDemoModal }: HeaderProps) {
 
                 {/* GitHub Link */}
                 <a
-                  href="https://github.com/your-org/fast-next-template"
+                  href="https://gitea.pragmazest.com/cardosofelipe/syndarix"
                   target="_blank"
                   rel="noopener noreferrer"
                   onClick={() => setMobileMenuOpen(false)}