fix: resolve CI coverage tool compatibility issues

- Update CI workflow to use --tests flag with cargo llvm-cov
- This ensures the testing module is properly available during coverage analysis
- Maintains backward compatibility with existing test structure

Addresses the 'file not found for module testing' error during coverage generation

Author: GriffinCanCode

.github/workflows/ci.yml

@@ -100,7 +100,7 @@ jobs:
         run: cargo install cargo-llvm-cov
 
       - name: Generate coverage
-        run: cargo llvm-cov --all-features --workspace --lcov --output-path lcov.info
+        run: cargo llvm-cov --tests --all-features --workspace --lcov --output-path lcov.info
 
       - name: Upload coverage to Codecov
         uses: codecov/codecov-action@v4