fix: add missing tools to hello-world and test-engineer templates

- hello-world: add file_write (LLM needs it for writing files)
- test-engineer: add web_fetch, web_search (needed for researching test patterns)

agents/test-engineer/agent.toml

@@ -62,6 +62,8 @@ tools = [
   "file_write",
   "file_list",
   "shell_exec",
+  "web_fetch",
+  "web_search",
   "memory_store",
   "memory_recall",
 ]