Update the build-dir shell function to usage zcurses instead of the
Python pick package to interactively select build directories, this
results in a more responsive user experience. Add argument parsing to
handle various use cases. Add prompt when the build command for the
selected build directory could not be detected, allowing the user to
specify the desired build command.
```
usage: build-dir [-h] [--build] [<directory>]
Find and select the current build directory interactively.
positional arguments:
<directory> the build directory to select
optional arguments:
-h, --help show this help message and exit
--build invoke a build after selection
```
