chore: add missing copyright in new files from infra branch (#10055)

Let's see if it passes

internal/blob/azureblob/azureblob.go

@@ -1,3 +1,9 @@
+// Copyright (C) 2025 The Syncthing Authors.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at https://mozilla.org/MPL/2.0/.
+
 package azureblob
 
 import (

internal/blob/interface.go

@@ -1,3 +1,9 @@
+// Copyright (C) 2025 The Syncthing Authors.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at https://mozilla.org/MPL/2.0/.
+
 package blob
 
 import (