Improve Haxe LS: configurable version/haxePath, top-level imports, CI docs, regression test

docs/02-usage/050_configuration.md

@@ -496,7 +496,9 @@ Supported settings:
 | Setting | Default | Description |
 |---|---|---|
 | `ls_path` | auto-discovered | Path to the Haxe language server binary (e.g., `/path/to/server.js`). |
+| `version` | `2.34.2` | Override the vshaxe extension version downloaded from Open VSX. SHA256 verification is only performed for the default version. |
 | `buildFile` | auto-discovered `.hxml` | Relative path to the `.hxml` build file used for compilation (e.g., `build/debug.hxml`). If not set, Serena searches the project for `.hxml` files (max depth 5, skipping dependency directories). |
+| `haxePath` | `haxe` from PATH | Path to the Haxe compiler executable. The LS delegates to this for code analysis. Useful when multiple Haxe versions are installed or when `haxe` is not on the PATH. |
 | `renameSourceFolders` | not set (LS default) | List of source directories for scoping rename operations (e.g., `["src", "lib"]`). If not set, the Haxe LS uses its own defaults. |
 
 Example (typically in `project.yml`, since these are project-specific):
@@ -505,6 +507,7 @@ Example (typically in `project.yml`, since these are project-specific):
 ls_specific_settings:
   haxe:
     buildFile: "build/debug.hxml"
+    haxePath: "/usr/local/bin/haxe"
     renameSourceFolders: ["src", "lib"]
 ```