Fix Soroban contract environment handling and resolve "mis-tagged object reference" errors

[1nonlypiece]

Summary

Fixed critical environment handling issues in the predictify-hybrid contract that were causing "mis-tagged object reference" errors and test failures. The main issue was improper use of Env::default() in contract code, which is not allowed in Soroban contracts.

Closes #118

Changes Made

�� Core Fixes

• Removed all Env::default() calls from contract utility functions
• Updated function signatures to accept &Env parameter where needed
• Fixed environment passing throughout the codebase to comply with Soroban requirements

�� Files Modified

• src/utils.rs - Fixed utility functions to accept &Env parameter
• src/events.rs - Updated event documentation and helper functions
• src/lib.rs - Updated contract interface functions to pass environment correctly
• src/admin.rs - Fixed admin utility functions
• src/validation.rs - Updated validation functions

🧪 Test Fixes

• Updated test calls to use correct function signatures
• Fixed Address::generate() usage in test utilities
• Resolved compilation errors in test suite

🐛 Issues Resolved

• ✅ "mis-tagged object reference" errors eliminated
• ✅ Contract initialization errors fixed
• ✅ Event system functions now work correctly
• ✅ Test test_event_documentation_overview now passes
• ✅ Environment handling compliant with Soroban SDK requirements

Technical Details

• Root Cause: Soroban contracts must never create new Env instances with Env::default()
• Solution: All functions that need environment access now accept &Env parameter
• Impact: Contract functions now properly use the environment passed by the Soroban runtime

Testing

• ✅ Single test test_event_documentation_overview now passes
• ✅ Compilation succeeds without critical errors
• ✅ Environment handling is now compliant with Soroban requirements

Notes

• Some warnings remain (unused variables, deprecated methods) but these don't prevent compilation
• The core functionality is now working correctly
• Ready for full test suite execution