Add local karma functionality for chat-specific karma tracking

[konard]

🎯 Summary

This PR implements local karma functionality that allows users to have separate karma values for each chat, in addition to their global karma.

Fixes #45

✨ Features Implemented

Core Functionality

• Local karma storage: Each user now has a local_karma dictionary storing karma values per chat ID
• Chat-specific karma tracking: Users can have different karma in different chats
• Independent from global karma: Local karma works alongside existing global karma without interference

Commands Added

• local karma / локальная карма - Display local karma for current chat
• local +/- - Vote to change local karma in current chat
• local +[NUMBER] / local -[NUMBER] - Transfer specific amount of local karma
• local top / локальный топ - Show local karma leaderboard for current chat
• local bottom / локальный низ - Show reverse local karma leaderboard

Technical Implementation

• Added local_karma field to user data structure as dict: {chat_id: karma_value}
• Implemented helper methods in BetterBotBaseDataService for local karma operations
• Created local karma versions of existing karma commands and builders
• Added comprehensive pattern matching for Russian and English aliases
• Extended help system to include local karma documentation

Testing

• Added comprehensive test suite (Test4LocalKarma) covering:
  • Local karma data storage and retrieval
  • Local karma string formatting
  • Local karma command functionality
  • Local karma user sorting and leaderboards
• All tests validate chat-specific karma isolation

Documentation

• Updated README.md with all new local karma commands
• Added command aliases table for local karma
• Extended in-bot help messages with local karma usage
• Documented all local karma features with examples

🔧 Technical Details

Data Structure

user.local_karma = {
    "2000000001": 15,  # Chat 1 karma
    "2000000002": -3,  # Chat 2 karma  
    "2000000003": 8    # Chat 3 karma
}

Key Methods Added

• BetterBotBaseDataService.get_local_karma(user, chat_id)
• BetterBotBaseDataService.set_local_karma(user, chat_id, karma_value)
• DataBuilder.build_local_karma(user, data, chat_id)
• DataBuilder.get_users_sorted_by_local_karma(vk, data, peer_id, chat_id)
• Commands.local_karma_message(), apply_local_karma(), local_top()

Backward Compatibility

✅ All existing global karma functionality preserved
✅ No breaking changes to existing commands or data structures
✅ Local karma is purely additive feature

🧪 Testing Strategy

• Unit tests verify local karma isolation between chats
• Tests confirm global karma remains unaffected
• Command parsing tests for all new patterns
• Leaderboard sorting tests with multiple users

📖 Usage Examples

Basic Local Karma

User: local karma
Bot: Ваша локальная карма в этом чате — [5].

User: local +
Bot: Локальная карма в этом чате изменена: [id123|John] [2]->[3].

Local Leaderboards

User: local top 3
Bot: [15] [id456|Alice] github.com/alice Python, C++
     [8] [id789|Bob] Rust, Go  
     [3] [id123|John] JavaScript

🚀 Ready for Review

All implementation is complete with comprehensive testing and documentation.

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