Enhance path handling for init files in ApiService

- Updated logic in `api.rs` to correctly handle cases where existing paths are init files, ensuring that children are placed in the appropriate directory.
- Improved clarity in comments to explain the handling of init files and their relationship to directory structure, contributing to better maintainability of the code.

src/web/api.rs

@@ -869,6 +869,15 @@ impl ApiService {
                 if !added.children.is_empty() {
                     let children_dir = if existing_path.is_dir() {
                         existing_path.to_path_buf()
+                    } else if existing_path
+                        .file_name()
+                        .and_then(|n| n.to_str())
+                        .map_or(false, |n| n.starts_with("init."))
+                    {
+                        // existing_path is an init file (e.g., DirFoo/init.luau).
+                        // The instance is already in directory format -- children go
+                        // into the same directory that contains the init file.
+                        existing_path.parent().unwrap_or(existing_path).to_path_buf()
                     } else {
                         // Standalone scripts cannot have children in Rojo's file format.
                         // We need to convert from standalone (e.g., MyScript.server.luau)