Reorganize repository into monorepo structure

Restructured the project to support multiple frontend applications:
- Move web app to web/ directory
- Create pezkuwi-sdk-ui/ for Polkadot SDK clone (planned)
- Create mobile/ directory for mobile app development
- Add shared/ directory with common utilities, types, and blockchain code
- Update README.md with comprehensive documentation
- Remove obsolete DKSweb/ directory

This monorepo structure enables better code sharing and organized
development across web, mobile, and SDK UI projects.

web/src/components/LanguageSwitcher.tsx

@@ -0,0 +1,59 @@
+import { useTranslation } from 'react-i18next';
+import { Button } from '@/components/ui/button';
+import {
+  DropdownMenu,
+  DropdownMenuContent,
+  DropdownMenuItem,
+  DropdownMenuTrigger,
+} from '@/components/ui/dropdown-menu';
+import { Globe } from 'lucide-react';
+import { languages } from '@/i18n/config';
+import { useEffect } from 'react';
+
+export function LanguageSwitcher() {
+  const { i18n } = useTranslation();
+
+  useEffect(() => {
+    // Update document direction based on language
+    const currentLang = languages[i18n.language as keyof typeof languages];
+    if (currentLang) {
+      document.documentElement.dir = currentLang.dir;
+      document.documentElement.lang = i18n.language;
+    }
+  }, [i18n.language]);
+
+  const changeLanguage = (lng: string) => {
+    i18n.changeLanguage(lng);
+    const lang = languages[lng as keyof typeof languages];
+    if (lang) {
+      document.documentElement.dir = lang.dir;
+      document.documentElement.lang = lng;
+    }
+  };
+
+  const currentLanguage = languages[i18n.language as keyof typeof languages] || languages.en;
+
+  return (
+    <DropdownMenu>
+      <DropdownMenuTrigger asChild>
+        <Button variant="ghost" size="sm" className="gap-2">
+          <Globe className="h-4 w-4" />
+          <span className="hidden sm:inline">{currentLanguage.name}</span>
+          <span className="text-lg">{currentLanguage.flag}</span>
+        </Button>
+      </DropdownMenuTrigger>
+      <DropdownMenuContent align="end" className="w-48">
+        {Object.entries(languages).map(([code, lang]) => (
+          <DropdownMenuItem
+            key={code}
+            onClick={() => changeLanguage(code)}
+            className={`cursor-pointer ${i18n.language === code ? 'bg-yellow-100 dark:bg-yellow-900' : ''}`}
+          >
+            <span className="text-lg mr-2">{lang.flag}</span>
+            <span>{lang.name}</span>
+          </DropdownMenuItem>
+        ))}
+      </DropdownMenuContent>
+    </DropdownMenu>
+  );
+}