fix(app-server): mark thread/turns/list and exclude_turns as experime… (#20499)

…ntal

We have some bugs to work out and it is not quite ready to consume as a
public API.

codex-rs/app-server/README.md

@@ -144,12 +144,12 @@ Example with notification opt-out:
 
 - `thread/start` — create a new thread; emits `thread/started` (including the current `thread.status`) and auto-subscribes you to turn/item events for that thread. When the request includes a `cwd` and the resolved sandbox is `workspace-write` or full access, app-server also marks that project as trusted in the user `config.toml`. Pass `sessionStartSource: "clear"` when starting a replacement thread after clearing the current session so `SessionStart` hooks receive `source: "clear"` instead of the default `"startup"`. For permissions, prefer experimental `permissions` profile selection; the legacy `sandbox` shorthand is still accepted but cannot be combined with `permissions`. Experimental `environments` selects the sticky execution environments for turns on the thread; omit it to use the server default, pass `[]` to disable environments, or pass explicit environment ids with per-environment `cwd`.
 - `thread/resume` — reopen an existing thread by id so subsequent `turn/start` calls append to it. Accepts the same permission override rules as `thread/start`.
-- `thread/fork` — fork an existing thread into a new thread id by copying the stored history; if the source thread is currently mid-turn, the fork records the same interruption marker as `turn/interrupt` instead of inheriting an unmarked partial turn suffix. The returned `thread.forkedFromId` points at the source thread when known. Accepts `ephemeral: true` for an in-memory temporary fork, emits `thread/started` (including the current `thread.status`), and auto-subscribes you to turn/item events for the new thread. Pass `excludeTurns: true` when the client plans to page fork history via `thread/turns/list` instead of receiving the full turn array immediately. Accepts the same permission override rules as `thread/start`.
+- `thread/fork` — fork an existing thread into a new thread id by copying the stored history; if the source thread is currently mid-turn, the fork records the same interruption marker as `turn/interrupt` instead of inheriting an unmarked partial turn suffix. The returned `thread.forkedFromId` points at the source thread when known. Accepts `ephemeral: true` for an in-memory temporary fork, emits `thread/started` (including the current `thread.status`), and auto-subscribes you to turn/item events for the new thread. Experimental clients can pass `excludeTurns: true` when they plan to page fork history via `thread/turns/list` instead of receiving the full turn array immediately. Accepts the same permission override rules as `thread/start`.
 - `thread/start`, `thread/resume`, and `thread/fork` responses include the legacy `sandbox` compatibility projection. Experimental clients can read response `permissionProfile` for the exact active runtime permissions and `activePermissionProfile` for the named or implicit built-in profile identity/provenance when known.
 - `thread/list` — page through stored rollouts; supports cursor-based pagination and optional `modelProviders`, `sourceKinds`, `archived`, `cwd`, and `searchTerm` filters. Each returned `thread` includes `status` (`ThreadStatus`), defaulting to `notLoaded` when the thread is not currently loaded.
 - `thread/loaded/list` — list the thread ids currently loaded in memory.
 - `thread/read` — read a stored thread by id without resuming it; optionally include turns via `includeTurns`. The returned `thread` includes `status` (`ThreadStatus`), defaulting to `notLoaded` when the thread is not currently loaded.
-- `thread/turns/list` — page through a stored thread’s turn history without resuming it; supports cursor-based pagination with `sortDirection`, `nextCursor`, and `backwardsCursor`.
+- `thread/turns/list` — experimental; page through a stored thread’s turn history without resuming it; supports cursor-based pagination with `sortDirection`, `nextCursor`, and `backwardsCursor`.
 - `thread/metadata/update` — patch stored thread metadata in sqlite; currently supports updating persisted `gitInfo` fields and returns the refreshed `thread`.
 - `thread/memoryMode/set` — experimental; set a thread’s persisted memory eligibility to `"enabled"` or `"disabled"` for either a loaded thread or a stored rollout; returns `{}` on success.
 - `memory/reset` — experimental; clear the current `CODEX_HOME/memories` directory and reset persisted memory stage data in sqlite while preserving existing thread memory modes; returns `{}` on success.
@@ -276,7 +276,7 @@ Valid `personality` values are `"friendly"`, `"pragmatic"`, and `"none"`. When `
 
 To continue a stored session, call `thread/resume` with the `thread.id` you previously recorded. The response shape matches `thread/start`. When the stored session includes persisted token usage, the server emits `thread/tokenUsage/updated` immediately after the response so clients can render restored usage before the next turn starts. You can also pass the same configuration overrides supported by `thread/start`, including `approvalsReviewer`.
 
-By default, `thread/resume` includes the reconstructed turn history in `thread.turns`. Pass `excludeTurns: true` to return only thread metadata and live resume state, then call `thread/turns/list` separately if you want to page the turn history over the network. In that mode the server also skips replaying restored `thread/tokenUsage/updated`, which avoids rebuilding turns just to attribute historical usage.
+By default, `thread/resume` includes the reconstructed turn history in `thread.turns`. Experimental clients can pass `excludeTurns: true` to return only thread metadata and live resume state, then call `thread/turns/list` separately if they want to page the turn history over the network. In that mode the server also skips replaying restored `thread/tokenUsage/updated`, which avoids rebuilding turns just to attribute historical usage.
 
 By default, resume uses the latest persisted `model` and `reasoningEffort` values associated with the thread. Supplying any of `model`, `modelProvider`, `config.model`, or `config.model_reasoning_effort` disables that persisted fallback and uses the explicit overrides plus normal config resolution instead.
 
@@ -304,7 +304,7 @@ To branch from a stored session, call `thread/fork` with the `thread.id`. This c
 { "method": "thread/started", "params": { "thread": { … } } }
 ```
 
-Like `thread/resume`, `thread/fork` also accepts `excludeTurns: true` to return only thread metadata in `thread.turns` and let the client page history with `thread/turns/list`. In that mode the server skips replaying restored `thread/tokenUsage/updated`, which keeps the fork path from rebuilding turns just to attribute historical usage.
+Like `thread/resume`, experimental clients can pass `excludeTurns: true` to `thread/fork` to return only thread metadata in `thread.turns` and page history with `thread/turns/list`. In that mode the server skips replaying restored `thread/tokenUsage/updated`, which keeps the fork path from rebuilding turns just to attribute historical usage.
 
 Experimental API: `thread/start`, `thread/resume`, and `thread/fork` accept `persistExtendedHistory: true` to persist a richer subset of ThreadItems for non-lossy history when calling `thread/read`, `thread/resume`, and `thread/fork` later. This does not backfill events that were not persisted previously.
 
@@ -418,9 +418,9 @@ Use `thread/read` to fetch a stored thread by id without resuming it. Pass `incl
 } }
 ```
 
-### Example: List thread turns
+### Example: List thread turns (experimental)
 
-Use `thread/turns/list` to page a stored thread’s turn history without resuming it. By default, results are sorted descending so clients can start at the present and fetch older turns with `nextCursor`. The response also includes `backwardsCursor`; pass it as `cursor` on a later request with `sortDirection: "asc"` to fetch turns newer than the first item from the earlier page.
+Use `thread/turns/list` with `capabilities.experimentalApi = true` to page a stored thread’s turn history without resuming it. By default, results are sorted descending so clients can start at the present and fetch older turns with `nextCursor`. The response also includes `backwardsCursor`; pass it as `cursor` on a later request with `sortDirection: "asc"` to fetch turns newer than the first item from the earlier page.
 
 ```json
 { "method": "thread/turns/list", "id": 24, "params": {