[TypeSpec Validation] Move compile from "postinstall" to "build" (Azu…

…re#24745)

- Compiling in "postinstall" breaks existing tools that copy "package.json" from repo root to spec folder

eng/pipelines/typespec-ci.yml

@@ -40,6 +40,10 @@ jobs:
     displayName: npm ls -a
     condition: succeededOrFailed()
 
+  - script: npm run build
+    displayName: npm run build
+    condition: succeededOrFailed()
+
   - template: templates/steps/typespec-ci.yml
     parameters:
       Folder: specification/contosowidgetmanager/Contoso.WidgetManager

package.json

@@ -12,6 +12,7 @@
     "@azure-tools/typespec-azure-resource-manager": "0.31.0",
     "@azure-tools/typespec-client-generator-core": "0.31.0",
     "@azure-tools/typespec-providerhub": "0.31.0",
+    "@azure-tools/typespec-validation": "file:eng/tools/TypeSpecValidation",
     "@typespec/compiler": "0.45.2",
     "@typespec/http": "0.45.0",
     "@typespec/openapi": "0.45.0",
@@ -20,11 +21,10 @@
     "@azure/avocado": "^0.8.4",
     "@types/prettier": "^2.7.2",
     "prettier": "^2.8.8",
-    "typescript": "~5.0.4",
-    "typespec-validation": "file:eng/tools/TypeSpecValidation"
+    "typescript": "~5.0.4"
   },
   "scripts": {
-    "postinstall": "npx --no tsc -- -p eng/tools/TypeSpecValidation"
+    "build": "npx --no tsc -- -p eng/tools/TypeSpecValidation"
   },
   "private": true
 }