Do not drop system-library .tsf units when the file stem differs from top-level symbols.
Add test_provider support for --interpreter=... and an interpreter integration test that validates full indexing plus completion+resolve snippet.
- Add class-name completion for `new` and `createobject("..."`.
- Generate constructor parameter snippets in completionItem/resolve.
- Support `obj.` instance member completion (methods/properties/fields).
- Infer `new`/`createobject` result types in SemanticModel TypeSystem.