feat(core-analytics): add React provider and useAnalytics hook

Adds a ./react subpath export to @repo/core-analytics containing
<AnalyticsProvider value={IAnalytics}> and useAnalytics(): IAnalytics.
useAnalytics() throws AnalyticsContextError when called outside a provider.
React Testing Library test verifies track() flows through context using
RecordingAnalytics. Switches vitest config to pick up .tsx test files
via environmentMatchGlobs and extends tsconfig to react-library.json
for JSX support.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

packages/core-analytics/src/react/analytics-provider.test.tsx

@@ -0,0 +1,41 @@
+import { describe, expect, it, vi } from "vitest";
+import { render, renderHook } from "@testing-library/react";
+import { RecordingAnalytics } from "@repo/core-testing";
+import {
+  AnalyticsContextError,
+  AnalyticsProvider,
+  useAnalytics,
+} from "@/react/index";
+
+function Tracker() {
+  const analytics = useAnalytics();
+  analytics.track("test.event");
+  return null;
+}
+
+describe("AnalyticsProvider", () => {
+  it("makes analytics available through context and track flows through", () => {
+    const recording = new RecordingAnalytics();
+
+    render(
+      <AnalyticsProvider value={recording}>
+        <Tracker />
+      </AnalyticsProvider>,
+    );
+
+    expect(recording.tracked).toContainEqual({ event: "test.event" });
+  });
+});
+
+describe("useAnalytics", () => {
+  it("throws AnalyticsContextError when called outside a provider", () => {
+    const spy = vi.spyOn(console, "error").mockImplementation(() => {});
+    try {
+      expect(() => renderHook(() => useAnalytics())).toThrow(
+        AnalyticsContextError,
+      );
+    } finally {
+      spy.mockRestore();
+    }
+  });
+});