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/utils/auth.ts

@@ -0,0 +1,86 @@
+/**
+ * Authentication and Authorization Utilities
+ * Security-critical: Founder wallet detection and permissions
+ */
+
+// SECURITY: Founder wallet address for beta testnet
+// This address has sudo rights and can perform privileged operations
+export const FOUNDER_ADDRESS = '5GgTgG9sRmPQAYU1RsTejZYnZRjwzKZKWD3awtuqjHioki45';
+
+/**
+ * Check if given address is the founder wallet
+ * @param address - Substrate address to check
+ * @returns true if address matches founder, false otherwise
+ */
+export const isFounderWallet = (address: string | null | undefined): boolean => {
+  if (!address) return false;
+  return address === FOUNDER_ADDRESS;
+};
+
+/**
+ * Validate substrate address format
+ * @param address - Address to validate
+ * @returns true if address is valid format
+ */
+export const isValidSubstrateAddress = (address: string): boolean => {
+  // Substrate addresses start with 5 and are 47-48 characters
+  return /^5[a-zA-Z0-9]{46,47}$/.test(address);
+};
+
+/**
+ * Permission levels for DEX operations
+ */
+export enum DexPermission {
+  // Anyone can perform these
+  VIEW_POOLS = 'view_pools',
+  ADD_LIQUIDITY = 'add_liquidity',
+  REMOVE_LIQUIDITY = 'remove_liquidity',
+  SWAP = 'swap',
+
+  // Only founder can perform these
+  CREATE_POOL = 'create_pool',
+  SET_FEE_RATE = 'set_fee_rate',
+  PAUSE_POOL = 'pause_pool',
+  WHITELIST_TOKEN = 'whitelist_token',
+}
+
+/**
+ * Check if user has permission for a specific DEX operation
+ * @param address - User's wallet address
+ * @param permission - Required permission level
+ * @returns true if user has permission
+ */
+export const hasPermission = (
+  address: string | null | undefined,
+  permission: DexPermission
+): boolean => {
+  if (!address || !isValidSubstrateAddress(address)) {
+    return false;
+  }
+
+  const founderOnly = [
+    DexPermission.CREATE_POOL,
+    DexPermission.SET_FEE_RATE,
+    DexPermission.PAUSE_POOL,
+    DexPermission.WHITELIST_TOKEN,
+  ];
+
+  // Founder-only operations
+  if (founderOnly.includes(permission)) {
+    return isFounderWallet(address);
+  }
+
+  // Everyone can view and trade
+  return true;
+};
+
+/**
+ * Get user role string for display
+ * @param address - User's wallet address
+ * @returns Human-readable role
+ */
+export const getUserRole = (address: string | null | undefined): string => {
+  if (!address) return 'Guest';
+  if (isFounderWallet(address)) return 'Founder (Admin)';
+  return 'User';
+};