Enhance user communication and improve UI components

- Update CLAUDE.md to mandate informal "Du" form for user communication in all UI text and emails.
- Modify LoginForm and RegisterForm components to reflect informal language in validation messages and placeholders.
- Add secure connection indicators in LoginForm for user awareness.
- Update alert component styles for better visual feedback.
- Introduce experimenta company information document for user reference.

app/components/ui/alert/index.ts

@@ -6,13 +6,15 @@ export { default as AlertDescription } from './AlertDescription.vue'
 export { default as AlertTitle } from './AlertTitle.vue'
 
 export const alertVariants = cva(
-  'relative w-full rounded-lg border p-4 [&>svg~*]:pl-7 [&>svg+div]:translate-y-[-3px] [&>svg]:absolute [&>svg]:left-4 [&>svg]:top-4 [&>svg]:text-foreground',
+  'relative w-full rounded-lg border p-4 flex items-center gap-3 [&>svg]:shrink-0 [&>svg]:text-foreground',
   {
     variants: {
       variant: {
         default: 'bg-background text-foreground',
         destructive:
           'border-destructive/50 text-destructive dark:border-destructive [&>svg]:text-destructive',
+        error:
+          'bg-white/15 border-l-4 border-warning text-white [&>svg]:text-warning',
       },
     },
     defaultVariants: {