Update README
Add template file for user presets

Remove now obsolete script file

Include BLAS/LAPACK v3.11.0 with MacOS 15 Sequoia

A newer XCode SDK on an older system can lead to a mismatch between the
text-based .dylib stubs and the actual Accelerate binary, leading to
linking errors.

Improve diagnostic output
Add linking to Accelerate to the CMAKE_{EXE|SHARED}_LINKER_FLAGS