Fix OAuth code exchange and go lint

Authorization-code exchange used ExternalClientID, which
is empty for registered clients and broke e2e token
grants. Pass the authenticated client's GID instead.

Also satisfy wsl_v5 blank-line rules, wire the delete
reference dialog through its mutation hook, and name the
filemanager logger.

Signed-off-by: Bryan Frimin <bryan@probo.com>

pkg/slug/slug.go

@@ -61,6 +61,7 @@ func MakeWithEntropy(s string) string {
 	if maxBase < 1 {
 		return suffix
 	}
+
 	if len(base) > maxBase {
 		base = strings.Trim(base[:maxBase], "-")
 		if base == "" {