chore: root typecheck now fans out to every workspace's own tsconfig

Closes the gap where app-level type errors escaped the standard gate
(root tsconfig covers packages/* only; apps each have their own).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

package.json

@@ -0,0 +1,20 @@
+{
+  "name": "sims-next",
+  "private": true,
+  "version": "0.1.0",
+  "type": "module",
+  "workspaces": [
+    "packages/*",
+    "apps/*"
+  ],
+  "scripts": {
+    "test": "vitest run",
+    "test:watch": "vitest",
+    "typecheck": "tsc -p tsconfig.json && npm run typecheck --workspaces --if-present"
+  },
+  "devDependencies": {
+    "@types/node": "^22.10.0",
+    "typescript": "^5.7.0",
+    "vitest": "^3.0.0"
+  }
+}