test(benchmarks): tag tasks as small change, larger implementation, or search

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

scripts/benchmarks/tasks/18-ts-deep-merge/task.json

@@ -1,4 +1,5 @@
 {
+  "category": "larger implementation",
   "prompt": "mergeConfig() drops nested settings from the base configuration when the override sets only some keys of a nested object. Merge nested objects deeply; arrays from the override replace base arrays, and neither input may be mutated.",
   "check": [
     "node",