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/components/home/HeroSection.tsx

@@ -41,7 +41,7 @@ export function HeroSection({ onOpenDemoModal }: HeroSectionProps) {
           >
             <div className="inline-flex items-center gap-2 rounded-full border bg-background/50 px-4 py-1.5 text-sm backdrop-blur">
               <span
-                className="inline-block h-2 w-2 rounded-full bg-green-500 animate-pulse"
+                className="inline-block h-2 w-2 rounded-full bg-success animate-pulse"
                 aria-hidden="true"
               />
               <span className="font-medium">MIT Licensed</span>