feat(python): add Pyrefly language server (#911)

Pyrefly (`pyrefly lsp`) joins basedpyright, Pyright and ty as a fallback Python language server. It is installable from Tools as a managed virtualenv tool and is listed among the interchangeable type checkers, before Ruff, so Ruff still runs after them.

Pyrefly only reports type errors in projects with a Pyrefly configuration (`pyrefly.toml` or `[tool.pyrefly]`); hover, completion and navigation work without one. A real-server test (ignored by default, needs `pyrefly` on PATH) covers startup, go-to-definition and diagnostics.

Co-authored-by: pcastro93 <[email protected]>

src/platform/locales/textCatalog.test.ts

@@ -149,6 +149,7 @@ const UNTRANSLATED = new Set<string>([
   "OpenIDEA",
   "Spring Boot",
   "PostgreSQL",
+  "Pyrefly",
   "Pyright",
   "pytest",
   "Rust",