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/src/export.rs

@@ -17,6 +17,7 @@ use crate::protocol::common::EXPERIMENTAL_CLIENT_METHODS;
 use anyhow::Context;
 use anyhow::Result;
 use anyhow::anyhow;
+use codex_protocol::protocol::RolloutLine;
 use schemars::JsonSchema;
 use schemars::schema_for;
 use serde::Serialize;
@@ -185,6 +186,12 @@ pub fn generate_json(out_dir: &Path) -> Result<()> {
     generate_json_with_experimental(out_dir, /*experimental_api*/ false)
 }
 
+pub fn generate_internal_json_schema(out_dir: &Path) -> Result<()> {
+    ensure_dir(out_dir)?;
+    write_json_schema::<RolloutLine>(out_dir, "RolloutLine")?;
+    Ok(())
+}
+
 pub fn generate_json_with_experimental(out_dir: &Path, experimental_api: bool) -> Result<()> {
     ensure_dir(out_dir)?;
     let envelope_emitters: Vec<JsonSchemaEmitter> = vec![

codex-rs/app-server-protocol/src/lib.rs

@@ -6,6 +6,7 @@ mod schema_fixtures;
 
 pub use experimental_api::*;
 pub use export::GenerateTsOptions;
+pub use export::generate_internal_json_schema;
 pub use export::generate_json;
 pub use export::generate_json_with_experimental;
 pub use export::generate_ts;