Replace "FastNext" branding with "PragmaStack" across the project

- Updated all references, metadata, and templates to reflect the new branding, including layout files, components, and documentation.
- Replaced hardcoded color tokens like `green-600` with semantic tokens (`success`, `warning`, etc.) for improved design consistency.
- Enhanced `globals.css` with new color tokens for success, warning, and destructive states using the OKLCH color model.
- Added comprehensive branding guidelines and updated the design system documentation to align with the new identity.
- Updated tests and mocks to reflect the branding changes and ensured all visual/verbal references match "PragmaStack".
- Added new `branding/README.md` and `branding` docs for mission, values, and visual identity definition.

frontend/src/app/[locale]/page.tsx

@@ -1,6 +1,6 @@
 /**
  * Homepage / Landing Page
- * Main landing page for the FastNext Template project
+ * Main landing page for the PragmaStack project
  * Showcases features, tech stack, and provides demos for developers
  */
 
@@ -67,7 +67,7 @@ export default function Home() {
         <div className="container mx-auto px-6 py-8">
           <div className="flex flex-col md:flex-row items-center justify-between gap-4">
             <div className="text-sm text-muted-foreground">
-              © {new Date().getFullYear()} FastNext Template. MIT Licensed.
+              © {new Date().getFullYear()} PragmaStack. MIT Licensed.
             </div>
             <div className="flex items-center gap-6 text-sm text-muted-foreground">
               <Link href="/demos" className="hover:text-foreground transition-colors">