rafidghanim/PBL-Alin — reverse-engineered prompt

Build me a simple web app for linear algebra using the existing Python project as the base. I want a clean GUI where someone can type in matrices or values from the keyboard, run an operation, see the result on screen, and click a Simpan Hasil button to download the output as a txt file.

Please wire up the placeholder app so the main menus actually work for Gauss elimination, Gauss Jordan, determinant, inverse matrix, matrix inversion method, LU factorization, eigen value and eigen vector, matrix diagonalization, and singular value decomposition. Keep the math logic separated from the web routes, with the algorithms in the operations area and the Flask routes just handling requests and responses. Use the existing modular structure, finish the templates enough so each feature is usable, and connect the API endpoint for operations if that fits.

Make it runnable locally at the current app address, and add or fix tests so the core calculations can be checked with pytest. If anything is unclear, look up current docs online if you need to.