Enhance referral program features and localization updates

- Implemented referral statistics retrieval to provide users with insights on invited friends and subscription purchases.
- Updated referral command handler to include new statistics in the response message, improving user engagement.
- Revised localization files for both English and Russian to reflect changes in the referral program messaging, enhancing clarity and user experience.

locales/en.json

@@ -77,7 +77,7 @@
   "no_button": "No",
   "trial_cancelled_short": "Activation cancelled.",
 
-  "referral_program_info_new": "Invite friends and earn bonuses!\n\nYour referral link:\n<code>{referral_link}</code>\n\n<b>Bonuses:</b>{bonus_details}",
+  "referral_program_info_new": "🎁 <b>Referral Program</b>\n\n📊 <b>Your stats:</b>\n👥 Friends invited: <b>{invited_count}</b>\n💳 Purchased subscription: <b>{purchased_count}</b>\n\n🔗 Your link:\n<code>{referral_link}</code>\n\n💰 <b>Invitation bonuses:</b>\n{bonus_details}\n\n📢 Share the link with friends and get bonuses!",
   "referral_bonus_per_period": "\n\n🎁 For a friend's {months}-month subscription:\n  ➢ You: <b>{inviter_bonus_days} days</b>\n  ➢ Friend: <b>{referee_bonus_days} days</b>",
   "no_bonus_days": "0",
   "referral_no_bonuses_configured": "\nNo referral bonuses configured.",
@@ -271,7 +271,7 @@
   "admin_user_logs_error": "❌ Error loading user actions",
   "admin_direct_message_signature": "\n\n---\n💬 Message from administrator",
   
-  "inline_referral_message": "🚀 Hey! Try this awesome VPN service!\n\n✨ Fast and reliable\n🔒 Complete anonymity\n🌍 Servers worldwide\n💎 Free trial period\n\nCheck it out: {referral_link}",
+
   "inline_referral_title": "🎁 Invite a Friend",
   "inline_referral_description": "Share referral link to get bonuses",
   
@@ -311,10 +311,13 @@
   "admin_promo_edit_step1_code": "✏️ <b>Editing Promo Code</b>\n\n<b>Step 1 of 4:</b> Promo Code\n\nCurrent code: <b>{current_code}</b>\n\nEnter new promo code (3-30 characters, letters and numbers only) or send current one to keep:",
   "admin_promo_edit_step2_bonus_days": "✏️ <b>Editing Promo Code</b>\n\n<b>Step 2 of 4:</b> Bonus Days\n\nCode: <b>{code}</b>\nCurrent days: <b>{current_days}</b>\n\nEnter number of bonus days (1-365):",
   "admin_promo_edit_step3_max_activations": "✏️ <b>Editing Promo Code</b>\n\n<b>Step 3 of 4:</b> Max Activations\n\nCode: <b>{code}</b>\nDays: <b>{days}</b>\nCurrent activations: <b>{current_max}</b>\n\nEnter maximum number of activations (1-10000):",
-  "admin_promo_edit_step4_validity": "✏️ <b>Editing Promo Code</b>\n\n<b>Step 4 of 4:</b> Validity Period\n\nCode: <b>{code}</b>\nDays: <b>{days}</b>\nActivations: <b>{max_act}</b>\nCurrent validity: <b>{current_validity}</b>\n\nEnter number of days the promo code is valid from today (1-365) or 0 for unlimited:",
+  "admin_promo_edit_step4_validity": "✏️ <b>Editing Promo Code</b>\n\n<b>Step 4 of 4:</b> Validity Period\n\nCode: <b>{code}</b>\nDays: <b>{days}</b>\nActivations: <b>{max_act}</b>\nCurrent validity: <b>{current_validity}</b>\n\nChoose the validity period for the promo code:",
+  "admin_promo_edit_unlimited_validity": "♾️ Unlimited",
+  "admin_promo_edit_set_validity": "⏰ Set Period",
+  "admin_promo_edit_enter_validity_days": "⏰ Enter the number of validity days for the promo code (1-365):",
   "admin_promo_updated_success": "✅ Promo code updated!\n\n🎟 Code: <b>{code}</b>\n🎁 Bonus days: <b>{days}</b>\n🔢 Max activations: <b>{max_act}</b>\n⏰ Valid until: <b>{validity}</b>",
   "admin_promo_update_failed": "❌ Error updating promo code",
-  "admin_promo_invalid_validity_days": "❌ Validity days must be from 0 to 365 days (0 = unlimited)",
+  "admin_promo_invalid_validity_days": "❌ Validity days must be from 1 to 365",
   
   "admin_logs_export_csv": "📄 Export to CSV",
   "admin_logs_csv_export_started": "📄 Starting log export to CSV...",
@@ -452,7 +455,7 @@
   "admin_panel_stats_fetch_error": "Error fetching panel data",
   "admin_panel_stats_error_details": "Details",
   
-  "inline_referral_message": "🎁 Get bonuses for friends!\n\nConnect friends to fast VPN and get bonus days for each new user.\n\n💰 Your referral link:\n{referral_link}",
+  "inline_referral_message": "🚀 Hey! Try this VPN - it's fast, reliable and affordable!\n\n🎁 Use my link to get bonus days with your subscription!\n\n{referral_link}",
   "inline_referral_title": "Referral link",
   "inline_referral_description": "Share referral link to get bonuses", 
   "inline_stats_title": "Bot statistics",