refactor(qa): split Matrix QA into optional plugin (#66723)

Merged via squash.

Prepared head SHA: 27241bd089
Co-authored-by: gumadeiras <5599352+gumadeiras@users.noreply.github.com>
Co-authored-by: gumadeiras <5599352+gumadeiras@users.noreply.github.com>
Reviewed-by: @gumadeiras

extensions/qa-matrix/src/cli.runtime.ts

@@ -0,0 +1,23 @@
+import { runMatrixQaLive } from "./runners/contract/runtime.js";
+import type { LiveTransportQaCommandOptions } from "./shared/live-transport-cli.js";
+import {
+  printLiveTransportQaArtifacts,
+  resolveLiveTransportQaRunOptions,
+} from "./shared/live-transport-cli.runtime.js";
+
+export async function runQaMatrixCommand(opts: LiveTransportQaCommandOptions) {
+  const runOptions = resolveLiveTransportQaRunOptions(opts);
+  const credentialSource = runOptions.credentialSource?.toLowerCase();
+  if (credentialSource && credentialSource !== "env") {
+    throw new Error(
+      "Matrix QA currently supports only --credential-source env (disposable local harness).",
+    );
+  }
+
+  const result = await runMatrixQaLive(runOptions);
+  printLiveTransportQaArtifacts("Matrix QA", {
+    report: result.reportPath,
+    summary: result.summaryPath,
+    "observed events": result.observedEventsPath,
+  });
+}