codex: address PR review feedback (#14988)

codex-rs/app-server-protocol/schema/json/codex_app_server_protocol.schemas.json

@@ -6113,9 +6113,17 @@
         "$schema": "http://json-schema.org/draft-07/schema#",
         "properties": {
           "delta": {
-            "description": "Raw bytes from the command stream (may not be valid UTF-8).",
+            "description": "Best-effort UTF-8 view of the output chunk for backwards compatibility.",
             "type": "string"
           },
+          "deltaBase64": {
+            "default": null,
+            "description": "Exact raw bytes for the chunk, base64-encoded.",
+            "type": [
+              "string",
+              "null"
+            ]
+          },
           "itemId": {
             "type": "string"
           },
@@ -12082,11 +12090,6 @@
                   "null"
                 ]
               },
-              "formattedOutput": {
-                "default": "",
-                "description": "The command's output after applying the model-facing formatter/truncation policy.",
-                "type": "string"
-              },
               "id": {
                 "type": "string"
               },
@@ -13148,6 +13151,7 @@
         "$schema": "http://json-schema.org/draft-07/schema#",
         "properties": {
           "command": {
+            "description": "Shell command string evaluated by the thread's configured shell. Unlike `command/exec`, this intentionally preserves shell syntax such as pipes, redirects, and quoting for legacy `!` parity.",
             "type": "string"
           },
           "threadId": {