fix: manifest.json template - appType must be string, version must be clientVersion

ManifestInfo.AppType is a string field (enum name parsed via
Enum.TryParse), and the version field key is 'clientVersion'
not 'version'. Updated template to match actual deserialization.

Discovered and verified via end-to-end integration test:
  Server → Client → Download → SHA256 verify → Extract → all pass

Author: JusterZhu

.claude/scripts/generate/templates/manifest.json.template

@@ -2,7 +2,7 @@
   "mainAppName": "{{PROJECT_NAME}}.exe",
   "updateAppName": "Upgrade{{PROJECT_NAME}}.exe",
   "updatePath": "./update/",
-  "appType": 1,
-  "version": "{{CLIENT_VERSION}}",
+  "appType": "Client",
+  "clientVersion": "{{CLIENT_VERSION}}",
   "productId": "{{PRODUCT_ID}}"
 }