~/.local/env PATH setup is not ideal in VS Code, on macOS

Apparently, VS Code adds `~/.local/bin` to the `PATH` before it starts the integrated terminal.

Then when the terminal starts macOS **prepends** `/etc/paths` (and probably the stuff in `/etc/paths.d`) to the `PATH`, and `/etc/paths` has `/usr/local/bin` (and others) by default.

So when `~/.local/bin/env` runs, `~/.local/bin` is already on the `PATH`, so it does **not** prepend it. But it is in the wrong position, because it is after `/usr/local/bin`, so it does not override system-installed binaries, like it was meant to be.

I verified all this on a vanilla macOS installation with a vanilla VS Code install.

I am not sure what the good fix would be for this, for now my installer will just unconditionally prepend `~/.local/bin/` to the `PATH`.

Start by tracing the macOS installer behavior around ~/.local/bin/env and how VS Code initializes the integrated terminal PATH. Reproduce the ordering on a vanilla macOS and VS Code installation, then determine the intended PATH precedence and verify that ~/.local/bin precedes /usr/local/bin without breaking other PATH entries.

Written by the indexing model from the issue text.