Refactor new editor boundaries and test ownership

new_editor/app/Features/Project/ProjectBrowserModelInternal.cpp

@@ -1,7 +1,5 @@
 #include "ProjectBrowserModelInternal.h"
 
-#include "Internal/StringEncoding.h"
-
 #include <algorithm>
 #include <cctype>
 #include <cwctype>
@@ -10,6 +8,28 @@
 
 namespace XCEngine::UI::Editor::App::ProjectBrowserModelInternal {
 
+namespace {
+
+std::string BuildUtf8String(std::u8string_view value) {
+    std::string result = {};
+    result.reserve(value.size());
+    for (const char8_t character : value) {
+        result.push_back(static_cast<char>(character));
+    }
+    return result;
+}
+
+std::u8string BuildU8String(std::string_view value) {
+    std::u8string result = {};
+    result.reserve(value.size());
+    for (const char character : value) {
+        result.push_back(static_cast<char8_t>(character));
+    }
+    return result;
+}
+
+} // namespace
+
 std::string ToLowerCopy(std::string value) {
     std::transform(
         value.begin(),
@@ -22,7 +42,11 @@ std::string ToLowerCopy(std::string value) {
 }
 
 std::string PathToUtf8String(const std::filesystem::path& path) {
-    return App::Internal::WideToUtf8(path.native());
+    return BuildUtf8String(path.u8string());
+}
+
+std::filesystem::path BuildPathFromUtf8(std::string_view value) {
+    return std::filesystem::path(BuildU8String(value));
 }
 
 std::string NormalizePathSeparators(std::string value) {
@@ -168,14 +192,14 @@ std::filesystem::path MakeUniqueFolderPath(
     const std::filesystem::path& parentPath,
     std::string_view preferredName) {
     std::filesystem::path candidatePath =
-        parentPath / App::Internal::Utf8ToWide(std::string(preferredName));
+        parentPath / BuildPathFromUtf8(preferredName);
     if (!std::filesystem::exists(candidatePath)) {
         return candidatePath;
     }
 
     for (std::size_t suffix = 1u;; ++suffix) {
         candidatePath =
-            parentPath / App::Internal::Utf8ToWide(
+            parentPath / BuildPathFromUtf8(
                 std::string(preferredName) + " " + std::to_string(suffix));
         if (!std::filesystem::exists(candidatePath)) {
             return candidatePath;
@@ -212,7 +236,7 @@ std::string BuildRenamedEntryName(
     }
 
     const std::filesystem::path requestedPath =
-        App::Internal::Utf8ToWide(std::string(requestedName));
+        BuildPathFromUtf8(requestedName);
     if (requestedPath.has_extension()) {
         return PathToUtf8String(requestedPath.filename());
     }