generate an internal json schema for RolloutLine (#14434)

### Why
i'm working on something that parses and analyzes codex rollout logs,
and i'd like to have a schema for generating a parser/validator.

`codex app-server generate-internal-json-schema` writes an
`RolloutLine.json` file

while doing this, i noticed we have a writer <> reader mismatch issue on
`FunctionCallOutputPayload` and reasoning item ID -- added some schemars
annotations to fix those

### Test

```
$ just codex app-server generate-internal-json-schema --out ./foo
```

generates an `RolloutLine.json` file, which i validated against jsonl
files on disk

`just codex app-server --help` doesn't expose the
`generate-internal-json-schema` option by default, but you can do `just
codex app-server generate-internal-json-schema --help` if you know the
command

everything else still works

---------

Co-authored-by: Codex <noreply@openai.com>

codex-rs/app-server-protocol/schema/json/v2/ThreadResumeParams.json

@@ -191,24 +191,6 @@
         }
       ]
     },
-    "FunctionCallOutputPayload": {
-      "description": "The payload we send back to OpenAI when reporting a tool call result.\n\n`body` serializes directly as the wire value for `function_call_output.output`. `success` remains internal metadata for downstream handling.",
-      "properties": {
-        "body": {
-          "$ref": "#/definitions/FunctionCallOutputBody"
-        },
-        "success": {
-          "type": [
-            "boolean",
-            "null"
-          ]
-        }
-      },
-      "required": [
-        "body"
-      ],
-      "type": "object"
-    },
     "GhostCommit": {
       "description": "Details of a ghost commit created from a repository state.",
       "properties": {
@@ -479,10 +461,6 @@
                 "null"
               ]
             },
-            "id": {
-              "type": "string",
-              "writeOnly": true
-            },
             "summary": {
               "items": {
                 "$ref": "#/definitions/ReasoningItemReasoningSummary"
@@ -498,7 +476,6 @@
             }
           },
           "required": [
-            "id",
             "summary",
             "type"
           ],
@@ -632,7 +609,7 @@
               "type": "string"
             },
             "output": {
-              "$ref": "#/definitions/FunctionCallOutputPayload"
+              "$ref": "#/definitions/FunctionCallOutputBody"
             },
             "type": {
               "enum": [
@@ -697,7 +674,7 @@
               "type": "string"
             },
             "output": {
-              "$ref": "#/definitions/FunctionCallOutputPayload"
+              "$ref": "#/definitions/FunctionCallOutputBody"
             },
             "type": {
               "enum": [