Deprecate 'az neon' command group with end-of-life notice (#9353)

* Deprecate 'az neon' command group with end-of-life notice and migration guidance

* refector message

* Update HISTORY.rst to include deprecation notice for 'az neon' command group

* Added license

Author: rsinghal26

src/neon/HISTORY.rst

@@ -30,3 +30,7 @@ Release History
 1.0.0b4
 ++++++
 * Update the CLI command description to support AI related queries.
+
+1.0.0b5
+++++++
+* Deprecate 'az neon' command group with end-of-life notice and migration guidance.

src/neon/azext_neon/_breaking_change.py

@@ -0,0 +1,15 @@
+# --------------------------------------------------------------------------------------------
+# Copyright (c) Microsoft Corporation. All rights reserved.
+# Licensed under the MIT License. See License.txt in the project root for license information.
+# --------------------------------------------------------------------------------------------
+
+from azure.cli.core.breaking_change import register_command_group_deprecate
+from azure.cli.core.breaking_change import register_other_breaking_change
+
+register_command_group_deprecate('az neon')
+
+message = """Deprecation Notice: The Neon Azure Native Integration is being deprecated and will
+reach end of life on January 31, 2026. Transfer your projects to a Neon managed organization
+today. Migration documentation is available at https://neon.com/docs/import/migrate-from-azure-native"""
+
+register_other_breaking_change('az neon', message)