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/vitest.config.ts

@@ -1,9 +1,17 @@
 import path from "node:path";
-import { mergeConfig } from "vitest/config";
+import { defineConfig, mergeConfig } from "vitest/config";
 import { nodeVitestConfig } from "@repo/core-typescript/vitest.base.node";
 
-export default mergeConfig(nodeVitestConfig, {
-  resolve: {
-    alias: { "@": path.resolve(__dirname, "./src") },
-  },
-});
+export default mergeConfig(
+  nodeVitestConfig,
+  defineConfig({
+    test: {
+      include: ["src/**/*.test.{ts,tsx}", "tests/**/*.test.{ts,tsx}"],
+      environmentMatchGlobs: [["**/*.test.tsx", "jsdom"]],
+      setupFiles: ["@repo/core-testing/setup/jsdom"],
+    },
+    resolve: {
+      alias: { "@": path.resolve(__dirname, "./src") },
+    },
+  }),
+);