WebAssembly support improvements

[pedrovgs]

Summary

This PR extends the WebAssembly support in Matft by implementing missing linear algebra functions that weren't available before.

Key changes:

• Add pure Swift eigenvalue decomposition (dgeev equivalent) using the QR algorithm with implicit double-shift
• Add comprehensive test coverage for WASM linear algebra operations including matrix inverse, determinant, and eigenvalue decomposition
• Enable CI workflow to run on pull requests
• Remove CLAPACK library and use instead just pure swift so we can avoid linking errors with other platforms and also reduce the final binary size for WASM.

Motivation

The initial WASM support (PR #55) provided basic functionality but was missing several important linear algebra operations. Specifically, dgeev (eigenvalue decomposition).

Pure Swift Eigenvalue Implementation

• Implements swiftEigenDecomposition function using:
  • Householder reduction to upper Hessenberg form
  • Implicit double-shift QR iteration for eigenvalue computation
  • SIMD-optimized vector operations where applicable
• Handles both real and complex conjugate eigenvalue pairs
• Computes left and right eigenvectors

Extended Test Coverage

• Adds 15+ new tests in WASIFallbackTests.swift covering:
  • Matrix inverse (2x2, 3x3, batched)
  • Determinant computation
  • Eigenvalue decomposition (diagonal, symmetric, complex eigenvalues)
  • Singular matrix error handling

[jjjkkkjjj]

Thanks a lot!