feat: decouple engine from renderer

[Satvik-Singh192]

Description

Refactored the project to decouple the physics engine from the desktop renderer and laid the foundation for WebAssembly support.

Changes Made

• Refactored the engine into a standalone AetherEngine library.
• Introduced AetherAPI as the public interface between the engine and renderer.
• Updated the desktop renderer to use AetherAPI instead of directly accessing PhysicsWorld.
• Added a separate WebAssembly build target using Emscripten.
• Reorganized the CMake build to support both Desktop and WASM targets.

Implementation Details

• Introduced AetherAPI and RenderBody to provide a clean abstraction over the engine.
• Separated engine and renderer dependencies to make the engine platform-independent.
• Added an initial WASM entry point and verified that the engine successfully compiles to WebAssembly.
• Preserved desktop functionality while preparing the codebase for future web-based rendering.

Checklist

Type:

• Bug Fix
• Feature
• Chore