feat(core-*): add Vitest configs + composition tests

core-api: appRouter exposes all 4 feature routers + blog procedure shape.
core-cms: payloadConfig registers all collections + globals.
core-trpc: client + provider exports verified.

Spec: §6.1, §6.6

packages/core-cms/tsconfig.json

@@ -2,8 +2,12 @@
   "extends": "@repo/core-typescript/base.json",
   "compilerOptions": {
     "outDir": "dist",
-    "rootDir": "src",
-    "lib": ["ES2022", "DOM"]
+    "rootDir": ".",
+    "lib": ["ES2022", "DOM"],
+    "types": ["vitest/globals"],
+    "paths": {
+      "@/*": ["./src/*"]
+    }
   },
   "include": ["src/**/*"],
   "exclude": ["node_modules", "dist"]