v2.0.0

Changes

• Replaced manual JSON string parsing with nlohmann/json library
• Fixed ID auto-increment bug with multi-digit task IDs
• Reduced main.cc from 350+ to 140 lines
• Added better error handling for invalid input
• Improved code maintainability with Task struct

Bug Fixes

• ID generation now works correctly for tasks with IDs > 9
• Rejects non-numeric IDs with clear error messages
• Better JSON formatting