feat: re-enable web search for clink codex using correct --enable flag

The previous fix (aceddb6) removed --search entirely, disabling web search.
This restores web search functionality using the correct --enable flag
that works with the codex exec subcommand.

Related to #338

conf/cli_clients/codex.json

@@ -3,7 +3,9 @@
   "command": "codex",
   "additional_args": [
     "--json",
-    "--dangerously-bypass-approvals-and-sandbox"
+    "--dangerously-bypass-approvals-and-sandbox",
+    "--enable",
+    "web_search_request"
   ],
   "env": {},
   "roles": {