“Pamela in Wonderland” rewinds the clock from 1996 to the mid-’80s so that we can learn how a perky and pretty, if naïve, waitress from Nowheresville, British Columbia, ended up in Tinseltown’s cynical crosshairs. The episode is short — not even 30 minutes — which is still long enough, given the version of the story it tells is so straightforward it never escapes cliché. A small-town girl is just hanging out — in Pam’s case, she’s at a football game with her dead-end boyfriend…