fix: configure test typings and root database linting

tsconfig.json

@@ -1,6 +1,11 @@
 /* To learn more about this file see: https://angular.io/config/tsconfig. */
 {
   "compileOnSave": false,
+  "files": [],
+  "references": [
+    { "path": "./tsconfig.app.json" },
+    { "path": "./tsconfig.spec.json" }
+  ],
   "compilerOptions": {
     "paths": { "db": ["./db.ts"] },
     "outDir": "./dist/out-tsc",