chore: Add basic tests for Studio's layer manipulation (#3164)

chore: Add test behaviors for Studio testing

chore: Add basic tests for studio layer adjustment

chore: Fixes from code review

app/module/dts/bindings/test-behaviors/zmk,behavior_add_layer.yaml

@@ -0,0 +1,8 @@
+# Copyright (c) 2025 The ZMK Contributors
+# SPDX-License-Identifier: MIT
+
+description: Layer Adder Behavior
+
+compatible: "zmk,behavior-add-layer"
+
+include: zero_param.yaml

app/module/dts/bindings/test-behaviors/zmk,behavior_move_layer.yaml

@@ -0,0 +1,8 @@
+# Copyright (c) 2025 The ZMK Contributors
+# SPDX-License-Identifier: MIT
+
+description: Layer Mover Behavior
+
+compatible: "zmk,behavior-move-layer"
+
+include: two_param.yaml

app/module/dts/bindings/test-behaviors/zmk,behavior_remove_layer.yaml

@@ -0,0 +1,8 @@
+# Copyright (c) 2025 The ZMK Contributors
+# SPDX-License-Identifier: MIT
+
+description: Layer Remover Behavior
+
+compatible: "zmk,behavior-remove-layer"
+
+include: one_param.yaml

app/module/dts/bindings/test-behaviors/zmk,behavior_set_layer_binding_at_idx.yaml

@@ -0,0 +1,13 @@
+# Copyright (c) 2025 The ZMK Contributors
+# SPDX-License-Identifier: MIT
+
+description: Layer Binding Setter Behavior
+
+compatible: "zmk,behavior-set-layer-binding-at-idx"
+
+include: two_param.yaml
+
+properties:
+  bindings:
+    type: phandle-array
+    required: true