mestra 0.1.2

mestra 0.1.2 grows a file by rows from C++ and makes every checked write atomic.

append_rows(rows, path) in C++ adds rows to an existing file without rewriting the rows it holds; the grown file is validated before it replaces the original, and anything that cannot be appended is refused with the difference named. A string id column now grows when an appended id is longer than the column.

Checked writes in Python, Julia and MATLAB build the file beside the destination, validate it and publish it with one rename, so a failure leaves an existing file untouched. docs/compatibility.md lists what each implementation can and cannot do. The format is unchanged: version 0, format = "mestra/0".

pip install mestra==0.1.2; MATLAB, C++ and Julia are installed from the tree as their READMEs say.