Add deprecation notice to AIShell repo (#423)

Author: StevenBucher98

README.md

@@ -1,5 +1,24 @@
 # AI Shell
 
+> [!IMPORTANT]
+> ⚠️ Project Status Update: AI Shell is no longer maintained.
+>
+> As of January 2026, the AI Shell project is no longer being actively maintained by the team.
+> Future releases or updates are unlikely.
+>
+> We want to thank everyone who experimented with the project, filed issues, and provided feedback.
+> Your engagement helped us explore what AI-assisted terminal experiences could look like.
+>
+> The repository will remain available in its current state for reference, but:
+>
+> - Issues and pull requests are not being monitored
+> - No new features or bug fixes are planned
+> - The project should be considered archived from an engineering standpoint
+>
+> We will update this notice if the status of the project changes.
+>
+> Thank you for your support and understanding.
+
 Welcome to the **AI Shell** repository! AI Shell is a CLI tool that brings the power of artificial
 intelligence directly to your command line! Designed to help you get command assistance from various
 AI assistants, AI Shell is a versatile tool to help you become more productive in the command line.