fix(ci): clear sam lint + golangci-lint findings

- template.yaml: drop redundant DependsOn (W3005) — Ref in LoggingConfig
  already implies BotFunctionLogGroup ordering.
- dynamodb_kv.go: remove unused errIsTableMissing and orphaned errors import.
- trading/prices.go: wrap deferred resp.Body.Close to satisfy errcheck.

internal/modules/trading/prices.go

@@ -87,7 +87,7 @@ func (c *PriceClient) FetchPrice(ctx context.Context, ticker string) (float64, e
 	if err != nil {
 		return 0, fmt.Errorf("trading: KBS request: %w", err)
 	}
-	defer resp.Body.Close()
+	defer func() { _ = resp.Body.Close() }()
 
 	if resp.StatusCode < 200 || resp.StatusCode >= 300 {
 		return 0, ErrNoPrice