refactor: enable strict type checking in manifest validation

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

Author: ericyangpan

scripts/validate/validate-manifests.mjs

@@ -37,7 +37,7 @@ const ajv = new Ajv2020({
   allErrors: true,
   verbose: true,
   strict: true,
-  strictTypes: false, // Disable strict types to allow unevaluatedProperties with allOf/ref
+  strictTypes: true,
   allowUnionTypes: true,
 })