test(snapshots): reconcile scripted run_code fixtures with the required description

The scripted (non-recorded) fixtures' run_code calls predate the required
description parameter, so replay rejected them at validation before any
dispatch: patch the scripted programs' args (tool/call, message blocks,
and chunk deltas together) and refresh goldens keylessly. Also picks up
the v4-pro re-records of the code-mode scenario pair whose live model
drifted from the overlay pin, and drops tmp-path churn.

examples/acp-agent/tests/snapshots/both-mode-turn/tool-schemas.expected.json

@@ -168,10 +168,15 @@
           "code": {
             "type": "string",
             "description": "The program: the body of an async TypeScript function."
+          },
+          "description": {
+            "type": "string",
+            "description": "Clear, concise description of what this program does in active voice, 5-10 words (shown in the UI). Examples: \"Count TODO markers across packages\"; \"Read failing test and its fixture\"; \"Rename config key in every cordis.yml\"."
           }
         },
         "required": [
-          "code"
+          "code",
+          "description"
         ]
       }
     },