Add documentation comment explaining the Unicode-aware project name validation regex

Co-authored-by: mitchdenny <513398+mitchdenny@users.noreply.github.com>

Author: Copilot

src/Aspire.Cli/Commands/NewCommand.cs

@@ -222,6 +222,12 @@ public virtual async Task<ITemplate> PromptForTemplateAsync(ITemplate[] validTem
 
 internal static partial class ProjectNameValidator
 {
+    // Regex for Unicode-aware project name validation:
+    // - Starts with Unicode letter or number [\p{L}\p{N}]
+    // - Can contain Unicode letters, numbers, connector punctuation (underscore), dash, dot, and combining marks
+    // - Must end with Unicode letter or number, optionally followed by combining marks
+    // - Length: 1-254 characters
+    // - Excludes unsafe characters: / \ : * ? " < > |
     [GeneratedRegex(@"^[\p{L}\p{N}]([\p{L}\p{N}\p{Pc}.\-\p{Mn}\p{Mc}]{0,252}[\p{L}\p{N}][\p{Mn}\p{Mc}]*|[\p{L}\p{N}\p{Pc}.\-\p{Mn}\p{Mc}]{0,252}[\p{L}\p{N}])?$", RegexOptions.Compiled)]
     internal static partial Regex GetAssemblyNameRegex();