impl convert module

[asukaminato0721]

Summary

Fixes part of #364

Implemented LSP refactor actions to mirror PyCharm’s “convert module ↔ package” behavior: module→package renames foo.py to foo/__init__.py, and package→module is only offered when the package directory contains only __init__.py (empty package), keeping content in __init__.py as the module body.

Added workspace-edit refactor actions (rename + delete operations; gated on client support for documentChanges/resourceOperations).

Test Plan

Added LSP interaction tests and fixtures.

[Copilot]

Pull request overview

This PR implements LSP refactor actions for converting between Python modules and packages, mirroring PyCharm's behavior. A module (e.g., foo.py) can be converted to a package (foo/__init__.py), and an empty package (containing only __init__.py and optionally __pycache__) can be converted back to a module.

Changes:

• Added workspace edit support for file rename and delete operations
• Implemented bidirectional module-package conversion code actions
• Added comprehensive LSP interaction tests

Reviewed changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated no comments.

File	Description
pyrefly/lib/lsp/non_wasm/server.rs	Added helper functions to check workspace edit capabilities, validate empty packages, and generate convert module/package code actions with appropriate rename and delete operations
pyrefly/lib/test/lsp/lsp_interaction/convert_module_package.rs	Added tests verifying both module-to-package and package-to-module conversion code actions with proper workspace edit operations
pyrefly/lib/test/lsp/lsp_interaction/mod.rs	Registered the new test module
pyrefly/lib/test/lsp/lsp_interaction/test_files/convert_module_package/*.py	Added test fixtures for module and empty package conversion scenarios

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[stroxler]

Should the new helpers be in a dedicated module rather than server.rs? I think in general we're trying to avoid too much growth in the central LSP modules as we add refactoring capabilities which often require a lot of code

[github-actions]

According to mypy_primer, this change doesn't affect type check results on a corpus of open source code. ✅

[meta-codesync]

@stroxler has imported this pull request. If you are a Meta employee, you can view this in D90779991.