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/blackjack.go

@@ -141,11 +141,11 @@ type bjTable struct {
 // ---------------------------------------------------------------------------
 
 type bjConfig struct {
-	TimeoutSeconds     int
-	AutoplayThreshold  int
-	MinBet             float64
-	MaxBet             float64
-	DebtLimit          float64
+	TimeoutSeconds    int
+	AutoplayThreshold int
+	MinBet            float64
+	MaxBet            float64
+	DebtLimit         float64
 }
 
 func loadBJConfig() bjConfig {
@@ -877,5 +877,3 @@ func (p *BlackjackPlugin) recordBJScore(userID id.UserID, net float64) {
 		recordBotDefeat(userID, "blackjack")
 	}
 }
-
-