Fix compilation errors and warnings

[DanielMarcos1]

This commit fixes several compilation errors preventing cargo check and cargo test from succeeding.

Changes include:

• Fixed E0425 and E0433 errors in src/geometry/vector.rs by correctly importing wide::f32x4 for SIMD operations.
• Resolved type placeholder issues in src/physics/world.rs's World struct, mapping them back to proper Rust types (Vector3d, f32, Polygon) under the new DOD structure.
• Removed unused physics::rigid_body module imports in src/physics/world.rs.
• Cleaned up several unnecessary mut bindings in world.rs and rigid_body.rs generating linter warnings.
• Hushed an unused variable warning in gpu.rs by prefixing submission_index with an underscore (_submission_index).

The codebase now builds successfully with cargo test and cargo check.

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PR created automatically by Jules for task 4610575985327991225 started by @DanielMarcos1

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