docs: add rule references and update copilot instructions

- Add @imports to CLAUDE.md for .claude/rules/ files
- Update copilot instructions to allow no-namespace code in Assets/Scripts/
- Add JEngine.UI namespace to instruction files

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
Signed-off-by: JasonXuDeveloper - 傑 <jason@xgamedev.net>

Author: JasonXuDeveloper

.github/instructions/code-review.instructions.md

@@ -32,7 +32,9 @@ For state accessed across Unity callbacks:
 ### 5. Namespace Compliance
 - Runtime: `JEngine.Core.*`
 - Editor: `JEngine.Core.Editor.*`
-- No namespace = flag for review
+- UI package: `JEngine.UI`
+- Hot update: `HotUpdate.Code`
+- **Exception**: `Assets/Scripts/` may contain user-level code without namespace (intentional for user customization)
 
 ## Common Issues to Flag
 

.github/instructions/jengine.instructions.md

@@ -13,7 +13,9 @@ JEngine is a Unity hot update framework using HybridCLR for runtime C# execution
 ### Namespaces
 - Runtime code: `JEngine.Core` or `JEngine.Core.*`
 - Editor code: `JEngine.Core.Editor` or `JEngine.Core.Editor.*`
+- UI package: `JEngine.UI`
 - Hot update code: `HotUpdate.Code`
+- **Exception**: `Assets/Scripts/` may contain user-level code without namespace (for user customization)
 
 ### Async/Await
 Always use `UniTask` instead of `Task`:

CLAUDE.md

@@ -1,5 +1,11 @@
 # JEngine Development Guidelines
 
+## Additional Rules
+
+@.claude/rules/coding-patterns.md
+@.claude/rules/commit-conventions.md
+@.claude/rules/package-creation.md
+
 ## Project Overview
 
 JEngine is a Unity framework for **runtime hot updates** in games. It enables developers to update game code and assets without requiring users to download new builds.