Organize shared code across web, mobile, and SDK UI projects

Centralized common code into shared/ folder to eliminate duplication and
improve maintainability across all three frontend projects (web, mobile,
pezkuwi-sdk-ui).

Changes:
- Added token types and constants to shared/types/tokens.ts
  - TokenInfo, PoolInfo, SwapQuote, and other DEX types
  - KNOWN_TOKENS with HEZ, PEZ, wUSDT definitions
  - Token logos (🟡🟣💵)

- Added Kurdistan color palette to shared/constants/
  - Kesk, Sor, Zer, Spî, Reş color definitions

- Added TOKEN_DISPLAY_SYMBOLS mapping (USDT vs wUSDT)

- Updated blockchain configuration in shared/blockchain/polkadot.ts
  - Added beta testnet endpoint (wss://beta-rpc.pezkuwi.art)
  - Defined DEFAULT_ENDPOINT constant

- Moved i18n to shared/i18n/
  - Centralized translation files for 6 languages (EN, TR, KMR, CKB, AR, FA)
  - Added LANGUAGES configuration with RTL support
  - Created isRTL() helper function

- Updated web and mobile to import from shared
  - web/src/types/dex.ts now re-exports from shared
  - web/src/contexts/PolkadotContext.tsx uses DEFAULT_ENDPOINT
  - mobile/src/i18n/index.ts uses shared translations
  - mobile/src/contexts/PolkadotContext.tsx uses DEFAULT_ENDPOINT

- Updated shared/README.md with comprehensive documentation

This architecture reduces code duplication and ensures consistency across
all frontend projects.

shared/i18n/index.ts

@@ -0,0 +1,74 @@
+/**
+ * Shared i18n configuration and translations
+ */
+
+// Import all translations
+import en from './locales/en.json';
+import tr from './locales/tr.json';
+import kmr from './locales/kmr.json';
+import ckb from './locales/ckb.json';
+import ar from './locales/ar.json';
+import fa from './locales/fa.json';
+
+/**
+ * Language configuration with RTL support
+ */
+export interface LanguageConfig {
+  code: string;
+  name: string;
+  nativeName: string;
+  rtl: boolean;
+}
+
+/**
+ * Available languages
+ */
+export const LANGUAGES: LanguageConfig[] = [
+  { code: 'en', name: 'English', nativeName: 'English', rtl: false },
+  { code: 'tr', name: 'Turkish', nativeName: 'Türkçe', rtl: false },
+  { code: 'kmr', name: 'Kurdish (Kurmanji)', nativeName: 'Kurmancî', rtl: false },
+  { code: 'ckb', name: 'Kurdish (Sorani)', nativeName: 'سۆرانی', rtl: true },
+  { code: 'ar', name: 'Arabic', nativeName: 'العربية', rtl: true },
+  { code: 'fa', name: 'Persian', nativeName: 'فارسی', rtl: true },
+];
+
+/**
+ * Default language code
+ */
+export const DEFAULT_LANGUAGE = 'en';
+
+/**
+ * Language storage key (for AsyncStorage/localStorage)
+ */
+export const LANGUAGE_STORAGE_KEY = '@pezkuwi_language';
+
+/**
+ * Translation resources
+ */
+export const translations = {
+  en,
+  tr,
+  kmr,
+  ckb,
+  ar,
+  fa,
+};
+
+/**
+ * Check if a language is RTL
+ * @param languageCode - Language code (e.g., 'ar', 'ckb', 'fa')
+ * @returns true if RTL, false otherwise
+ */
+export function isRTL(languageCode: string): boolean {
+  const lang = LANGUAGES.find(l => l.code === languageCode);
+  return lang?.rtl || false;
+}
+
+/**
+ * Get language configuration
+ * @param languageCode - Language code
+ * @returns Language configuration or undefined
+ */
+export function getLanguageConfig(languageCode: string): LanguageConfig | undefined {
+  return LANGUAGES.find(l => l.code === languageCode);
+}