gofmt: bring internal/ and cmd/ back to gofmt -l clean

Mechanical `gofmt -w ./internal ./cmd`. Mostly struct-field realignment that
had drifted, plus a few trailing-newline fixes. No behaviour change — gofmt is
semantics-preserving, and build/vet/test are green either side.

Split out from the code-review fixes that follow so those stay reviewable
instead of hiding inside a wall of realignment.

internal/plugin/adventure_flavor_pets.go

@@ -275,6 +275,7 @@ var PetCatDeflect = []string{
 		"Your cat is already somewhere else.\n\nIt blinks.\n\nNot at you.\n\nAt nothing.\n\n" +
 		"The way cats do.",
 }
+
 // Fires randomly in the morning DM. Cat has left something.
 // Results in a defense boost for the day.
 // The cat is proud. The cat will never stop doing this.