feat(apps): add unit tests for providers + bind-production + cms config

web-next: bindAllProduction calls all 4 feature binders exactly once;
Providers renders children. web-tanstack: equivalent providers + bind tests.
cms: payload.config exports a SanitizedConfig with all expected collections.

Spec: §6.7, §9

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

apps/web-tanstack/vitest.config.ts

@@ -0,0 +1,8 @@
+import path from "node:path";
+import { mergeConfig } from "vitest/config";
+import { jsdomVitestConfig } from "@repo/core-typescript/vitest.base.jsdom";
+
+export default mergeConfig(jsdomVitestConfig, {
+  esbuild: { jsx: "automatic" },
+  resolve: { alias: { "@": path.resolve(__dirname, "./src") } },
+});