Upstream patch `patch-python-getpath-3.14.patch`

[`patch-python-getpath-3.14.patch`](https://github.com/astral-sh/python-build-standalone/blob/06b721601b4492853ebf58f7105bc7957edf49b1/cpython-unix/patch-python-getpath-3.14.patch)

Adjusts the Python startup logic (getpath.py) to properly locate the installation, even when invoked through a symlink or through an incorrect argv[0].

c.f. #896

Start with cpython-unix/patch-python-getpath-3.14.patch and the upstream getpath.py startup logic it modifies. Trace how installation paths are resolved for symlinked execution and an incorrect argv[0], then verify that both invocation cases locate the intended installation without changing other startup behavior.

Written by the indexing model from the issue text.