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-next/package.json

@@ -7,6 +7,7 @@
     "build": "echo 'Next.js build requires full environment — use pnpm dev or docker'",
     "dev": "next dev --port 3000",
     "lint": "eslint .",
+    "test": "vitest run --passWithNoTests",
     "test:e2e": "playwright test",
     "test:e2e:install": "playwright install --with-deps chromium",
     "typecheck": "tsc --noEmit"
@@ -33,9 +34,15 @@
   "devDependencies": {
     "@playwright/test": "^1.50.0",
     "@repo/core-eslint": "workspace:*",
+    "@repo/core-testing": "workspace:*",
     "@repo/core-typescript": "workspace:*",
+    "@testing-library/jest-dom": "^6.5.0",
+    "@testing-library/react": "^16.0.0",
+    "@testing-library/user-event": "^14.5.0",
     "@types/node": "^22.0.0",
     "@types/react": "^19.0.0",
-    "@types/react-dom": "^19.0.0"
+    "@types/react-dom": "^19.0.0",
+    "jsdom": "^25.0.0",
+    "vitest": "^3.0.0"
   }
 }