Improve fee math coverage and clean up clippy warnings

[Ayushjhax]

Summary

• Remove unused imports from jupiter-aggregator-common/src/lib.rs
• Fix clippy::needless_update warning in jupiter-core/src/math/swap_curve_info.rs
• Add unit tests for fee calculations in jupiter-core/src/math/fees.rs

Changes

Cleanup:

• Removed 7 unused imports causing clippy warnings
• Simplified SwapResult construction by removing redundant ..Default::default()

Tests:

• Added 3 unit tests covering fee percentage calculations:
  • Fee percentage summation (trade + owner fees)
  • Zero denominator handling
  • Fee delegation to underlying implementation

Testing

cargo test # All tests pass ✅
cargo clippy --all-targets # No new warnings ✅## Impact

• ✅ No breaking changes
• ✅ Improved test coverage
• ✅ Reduced clippy warnings