you left commented-out while in $feed.html, and when you have repetitive code like

hadd -m $+(feed.,$hget(feed,id)) trunc %trunc

you can shorten it by setting the cmd as a var and just referencing the var, i.e.

var %variable .hadd -m
%variable trunc %trunc

but thats just so you don't have to type as much.

you only need one -m tag in your hadd's as the table would have been created by the first

rest looks good though.