Refactor weight management in WeightStore to use checked arithmetic f…

[TKorr]

…or safety. Replace debug assertions with runtime assertions to ensure invariants are maintained during weight updates. This change enhances error handling and prevents potential underflows in total weight calculations during insertions and removals.

Description

Related Issue

Fixes #

Type of Change

• 🐛 Bug fix (non-breaking change that fixes an issue)
• ✨ New feature (non-breaking change that adds functionality)
• 💥 Breaking change (fix or feature that would cause existing functionality to change)
• 📝 Documentation update
• 🔧 Refactoring (no functional changes)
• ⚡ Performance improvement
• 🧪 Test addition or modification

How Has This Been Tested?

• Unit tests
• Integration tests
• Manual testing

Test environment:

• OS:
• Rust version:

Checklist

• My code follows the project's coding standards
• I have run cargo fmt and cargo clippy
• I have added tests for my changes
• All new and existing tests pass (cargo test)
• I have updated the documentation as needed
• I have added an entry to CHANGELOG.md (if applicable)

Screenshots (if applicable)

Additional Notes