I would do:

set tw=77

ggShift vG to select the text,

< to kill the leading spaces,

gq to wrap the text.

I would do:

:set tw=77

ggShift vG to select the text,

:left to kill the leading spaces,

gv to restore the selection,

gq to wrap the text.

I would do:

set tw=77

Shift vgq

I would do:

set tw=77

ggShift vG to select the text,

< to kill the leading spaces,

gq to wrap the text.