feat: add multi-engine regex flavour support

tests/conformance/python.conformance.test.ts

@@ -6,6 +6,7 @@ import {
   PythonEngineAdapter,
   PYODIDE_ENGINE_VERSION,
   PYTHON_ENGINE_VERSION,
+  PYTHON_FLAVOUR_VERSION,
 } from "../../src/regex/execution/adapters/python/PythonEngineAdapter";
 import type {
   PyodideModule,
@@ -28,7 +29,7 @@ function request(
 ): RegexExecutionRequest {
   return {
     flavour: "python",
-    flavourVersion: PYTHON_ENGINE_VERSION,
+    flavourVersion: PYTHON_FLAVOUR_VERSION,
     pattern: "a",
     flags: ["g"],
     subject: "a",
@@ -68,7 +69,7 @@ describe("CPython re 3.14.2 conformance through self-hosted Pyodide", () => {
       expect.objectContaining({
         flavour: "python",
         engineName: "CPython re via Pyodide",
-        engineVersion: "CPython 3.14.2 re",
+        engineVersion: PYTHON_ENGINE_VERSION,
         runtimeVersion: expect.stringContaining("Pyodide 314.0.3"),
         offsetUnit: "code-point",
       }),