Added copyright headers to files missing them

Applied the standard MIT license header to all project-owned C, header,
assembly, shell, and Python files that were missing a copyright notice.
Third-party, toolchain startup, and auto-generated files were excluded.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

scripts/install.sh

@@ -1,4 +1,15 @@
 #!/bin/bash
+##############################################################################
+# Copyright (c) 2024 Microsoft Corporation
+# Copyright (c) 2026 Eclipse ThreadX contributors
+#
+# This program and the accompanying materials are made available under the
+# terms of the MIT License which is available at
+# https://opensource.org/licenses/MIT.
+#
+# SPDX-License-Identifier: MIT
+##############################################################################
+
 #
 
 # Remove large folder