* Replace spline with PchipInterpolatorHelper in flow compensator
Swapped out the tk::spline implementation for PchipInterpolatorHelper in SmallAreaInfillFlowCompensator. Updated member types and method calls to use the new interpolator for improved flow compensation modeling.
* Enforce strictly increasing flow compensation factors
Added a check to ensure that flow compensation factors in SmallAreaInfillFlowCompensator strictly increase with extrusion length, throwing an exception if this condition is not met. This improves input validation and prevents invalid compensation models.
* Add context to Small Area Flow Compensation errors
Prefixed error messages in SmallAreaInfillFlowCompensator with 'Small Area Flow Compensation' for improved clarity and debugging. Also rethrows exceptions after logging to ensure proper error propagation.
* Remove spline library from dependencies
Eliminated the spline header-only library from the project by deleting its CMake configuration and header file, and updating documentation and build scripts to remove references to spline. This streamlines the dependencies and build process.
Move many third-party components' source codes from the src folder to a new folder called deps_src. The goal is to make the code structure clearer and easier to navigate.
