New surface point class and example using Dirichlet Trace

[jdoelz]

This pull request enhances the handling of SurfacePoints by introducing a new SurfacePoint class. Previously, SurfacePoints were simply a relabelling of a fixed-length eigenvector, which made data access based on segments somewhat cumbersome for users.

This update aims improve usability by eliminating the need for explicit index access. The new class provides intuitive functions for easy access to geometric entities, streamlining the user experience.

Please note that all files utilizing SurfacePoints will need to be updated accordingly.

[Copilot]

Pull Request Overview

This pull request introduces a new SurfacePoint class along with an example demonstrating the Dirichlet Trace to improve the usability of geometric data access. Key changes include:

• Replacing raw Eigen vector segment accesses with intuitive getter functions (e.g. get_f(), get_xi(), get_w(), etc.) across Laplace, Helmholtz, and HomogenisedLaplace modules.
• Updating geometry and basis function evaluations to leverage the new SurfacePoint interface.
• Adjusting related files in Geometry, AnsatzSpace, and supporting modules to work with the new SurfacePoint class.

Reviewed Changes

Copilot reviewed 20 out of 42 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
Bembel/src/Laplace/*	Updated SurfacePoint accesses for Single/DoubleLayer operators using getter methods.
Bembel/src/Helmholtz/*	Migrated segment-based geometry evaluations to the new SurfacePoint API.
Bembel/src/HomogenisedLaplace/*	Updated kernel and integrand evaluations to use SurfacePoint getters.
Bembel/src/Geometry/SurfacePoint.hpp	Replaced typedef with a class interface that encapsulates geometry and quadrature data.
Bembel/src/Geometry/Patch.hpp	Modified updateSurfacePoint to use the new API and reuse the internal buffer of SurfacePoint.
Bembel/src/AnsatzSpace/*	Adjusted basis function evaluations and projections to use get_xi() instead of raw segment access.
Bembel/LinearForm	Added a new include for DirichletTraceOnReferenceDomain to support the updated trace interface.

[Copilot]

Consider using the allocated buffer size rather than a fixed value (12 * sizeof(double)) in the memset call, so that all of the buffer is properly cleared when polynomial degrees change.

Suggested change

	std::memset(buffer, 0, 12 * sizeof(double));
	std::memset(buffer, 0, sizeof(double) * (2 * (polynomial_degree_x_ + polynomial_degree_y_) + 12));