Fix claude code cli environment variable detection (#670)

* Fix Claude Code CLI environment variable detection

Update the Claude Code CLI detection logic to check for 'CLAUDECODE' and 'CLAUDE_CODE_ENTRYPOINT' environment variables instead of 'CLAUDE_CODE' and 'ANTHROPIC_CLI'. This ensures accurate detection of the Claude Code CLI environment.

* Update Directory.Build.props

Author: SimonCropp

src/DiffEngine/AiCliDetector.cs

@@ -16,7 +16,7 @@ static AiCliDetector()
 
         // Claude Code
         // https://docs.anthropic.com/en/docs/build-with-claude/claude-cli
-        IsClaudeCode = variables.Contains("CLAUDE_CODE") || variables.Contains("ANTHROPIC_CLI");
+        IsClaudeCode = variables.Contains("CLAUDECODE") || variables.Contains("CLAUDE_CODE_ENTRYPOINT");
 
         Detected = IsCopilot ||
                    IsAider ||

src/Directory.Build.props

@@ -2,7 +2,7 @@
 <Project>
   <PropertyGroup>
     <NoWarn>CS1591;CS0649;NU1608;NU1109</NoWarn>
-    <Version>18.1.0</Version>
+    <Version>18.1.1</Version>
     <AssemblyVersion>1.0.0</AssemblyVersion>
     <PackageTags>Testing, Snapshot, Diff, Compare</PackageTags>
     <Description>Launches diff tools based on file extensions. Designed to be consumed by snapshot testing libraries.</Description>