[SuparvaCode]

Description

In Unreal Engine C++ modules (and standard modular C++ projects), code is organized into Public/ (headers) and Private/ (implementation .cpp and internal headers).

Because DEFAULT_SECURITY_IGNORE_DIRS contains 'private/', isSecurityConcern was previously flagging ordinary C++ implementation files like Source//Private/ExampleActor.cpp as security concerns, preventing Agent mode from reading or editing them.

This change:

• Allows C++ and source files (.cpp, .cc, .cxx, .c, .h, .hpp, .hxx, .inl, .cs) located in Source//Private/ or Private/ directories, unless they match security-sensitive file patterns (like .key, .pem, .env).
• Adds unit tests covering Unreal Engine module paths and nested Private directories while ensuring secret files remain blocked.

Resolves #13420

Checklist

• I've read the contributing guide
• The relevant docs, if any, have been updated or created
• The relevant tests, if any, have been updated or created

Tests

Added test cases to core/indexing/ignore.vitest.ts:

• Verified Source/ExampleModule/Private/ExampleActor.cpp, .h, and nested subdirectories return false.
• Verified absolute workspace paths like c:/Users/name/Documents/.../Private/ExampleActor.cpp return false.
• Verified sensitive files like Source/.../Private/secret.key and Private/.env continue to return true.

[github-actions]

All contributors have signed the CLA ✍️ ✅
_{Posted by the CLA Assistant Lite bot.}

[SuparvaCode]

I have read the CLA Document and I hereby sign the CLA