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/lib/supabase.ts

@@ -0,0 +1,13 @@
+import { createClient } from '@supabase/supabase-js';
+
+// Initialize Supabase client from environment variables
+const supabaseUrl = import.meta.env.VITE_SUPABASE_URL;
+const supabaseKey = import.meta.env.VITE_SUPABASE_ANON_KEY;
+
+if (!supabaseUrl || !supabaseKey) {
+  console.warn('Supabase credentials not found in environment variables');
+}
+
+const supabase = createClient(supabaseUrl, supabaseKey);
+
+export { supabase };