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/dnd_expedition_temporal_test.go

@@ -366,8 +366,8 @@ func TestUnderforge_FortifiedRestReducesHeat(t *testing.T) {
 	defer cleanupExpeditions(uid)
 
 	exp := &Expedition{
-		ID:          "fake-uf",
-		ZoneID:      ZoneUnderforge,
+		ID:            "fake-uf",
+		ZoneID:        ZoneUnderforge,
 		TemporalStack: 5,
 	}
 	// Insert minimal row so updateTemporalStack works.