RE: by default, point should not enter the minibuffer prompt

[Drew Adams]

> The problem is that you are using `forward-line'.  It is a
> low-level function that does not do any sort of checking.
> Emacs commands intended for user use (C-a, C-p, etc) should
> act correctly and avoid the prompt.
...
> The aim is to make normal usage convenient (by avoiding the prompt),
> while still giving the user freedom to access that text if he really
> wants to.

Got it.

I'll change my minibuffer C-a command to DTRT. Thx.