repo: add mpl copyright headers

diff --git a/cpu.go b/cpu.go
index 502a8cc..2bceceb 100644
--- a/cpu.go
+++ b/cpu.go

@@ -1,3 +1,6 @@
+// Copyright (c) The M1CPU Authors
+// SPDX-License-Identifier: MPL-2.0
+
 //go:build darwin && arm64 && cgo
 
 package m1cpu

diff --git a/cpu_test.go b/cpu_test.go
index ed38452..afe8605 100644
--- a/cpu_test.go
+++ b/cpu_test.go

@@ -1,3 +1,6 @@
+// Copyright (c) The M1CPU Authors
+// SPDX-License-Identifier: MPL-2.0
+
 //go:build darwin && arm64 && cgo
 
 package m1cpu

diff --git a/examples_test.go b/examples_test.go
index 9e57bd4..8548bcc 100644
--- a/examples_test.go
+++ b/examples_test.go

@@ -1,3 +1,6 @@
+// Copyright (c) The M1CPU Authors
+// SPDX-License-Identifier: MPL-2.0
+
 package m1cpu
 
 import (

diff --git a/incompatible.go b/incompatible.go
index d425025..4b90403 100644
--- a/incompatible.go
+++ b/incompatible.go

@@ -1,3 +1,6 @@
+// Copyright (c) The M1CPU Authors
+// SPDX-License-Identifier: MPL-2.0
+
 //go:build !darwin || !arm64 || !cgo
 
 package m1cpu

diff --git a/incompatible_test.go b/incompatible_test.go
index fe89ee5..1af52ef 100644
--- a/incompatible_test.go
+++ b/incompatible_test.go

@@ -1,3 +1,6 @@
+// Copyright (c) The M1CPU Authors
+// SPDX-License-Identifier: MPL-2.0
+
 //go:build !darwin || !arm64 || !cgo
 
 package m1cpu