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/cms/package.json

@@ -7,6 +7,7 @@
     "build": "echo 'CMS build requires database — use docker compose or pnpm dev'",
     "dev": "next dev --port 3001",
     "lint": "eslint .",
+    "test": "vitest run --passWithNoTests",
     "typecheck": "tsc --noEmit",
     "generate:types": "payload generate:types"
   },
@@ -24,9 +25,11 @@
   },
   "devDependencies": {
     "@repo/core-eslint": "workspace:*",
+    "@repo/core-testing": "workspace:*",
     "@repo/core-typescript": "workspace:*",
     "@types/node": "^22.0.0",
     "@types/react": "^19.0.0",
-    "@types/react-dom": "^19.0.0"
+    "@types/react-dom": "^19.0.0",
+    "vitest": "^3.0.0"
   }
 }