Precompute app-server protocol exports (#36212)

## Why

Normal app-server protocol builds do not need the `ts-rs` and `schemars`
implementations used to generate schema exports.

## What changed

- Embed compressed stable and experimental TypeScript and JSON schema exports,
  and serve the existing export APIs from those artifacts.
- Use no-op schema derives in non-test builds while keeping the real generators
  available for fixture regeneration and tests.
- Move schema fixture regeneration behind a Python helper and update
  `just write-app-server-schema --experimental` to refresh the experimental
  embedded exports.

## Testing

- Verify embedded exports match freshly generated stable and experimental
  schemas.
- Verify export options and on-disk output remain compatible.

GitOrigin-RevId: e8536338b457e6eec34bdf29ec0684144bd13734

codex-rs/app-server-protocol/BUILD.bazel

@@ -2,6 +2,7 @@ load("//:defs.bzl", "codex_rust_crate")
 
 codex_rust_crate(
     name = "app-server-protocol",
+    compile_data = glob(["schema/precomputed/**"]),
     crate_name = "codex_app_server_protocol",
     test_data_extra = glob(
         ["schema/**"],