feat: update to open api version 235.16.3 (#328)

Regenerates the client from the `chat` serverside spec at **v235.16.3**
(previously v233.25.1, #326).

## Moderation: policy test sets & runs

New endpoints for creating labelled test sets and running the active
moderation policy against them:

- `ModerationApi.createPolicyTestSet` — `POST
/moderation/policy_tests/sets`
- `ModerationApi.listPolicyTestSets` — `GET
/moderation/policy_tests/sets`
- `ModerationApi.getPolicyTestSet` / `deletePolicyTestSet` — `GET|DELETE
/moderation/policy_tests/sets/{id}`
- `ModerationApi.startPolicyTestRun` — `POST
/moderation/policy_tests/sets/{id}/runs`
- `ModerationApi.getPolicyTestRun` — `GET
/moderation/policy_tests/runs/{id}`

Models: `CreatePolicyTestSetRequest`, `PolicyTestSet`,
`PolicyTestSetResponse`, `PolicyTestSetListResponse`, `PolicyTestRow`,
`PolicyTestSeedSpec`, `PolicyTestRun`, `PolicyTestRunResponse`,
`PolicyTestRunMetrics`, `PolicyTestResult`, `PolicyTestTotals`,
`PolicyTestLabelDrift`.

`ModerationApi.listQueues` now accepts an optional `user_id`.

## Imports: external storage configuration

- `CommonApi.getImporterExternalStorage` /
`upsertImporterExternalStorage` / `deleteImporterExternalStorage` —
`GET|PUT|DELETE /imports/v2/external-storage`
- `CommonApi.validateImporterExternalStorage` — `POST
/imports/v2/external-storage/validate`

Supports S3 and GCS via `UpsertExternalStorageRequest` (`aws_s3` /
`gcs`).

## Video: daily digest

- `VideoApi.getDailyDigest` — `GET /video/stats/daily_digest`, optional
`date` and `app_id`.

Adds the digest model tree: `GetDailyDigestResponse`, `BroadcastDigest`,
`BroadcastDailyRollup`, `BroadcastInfo`, `BroadcastSegment`,
`DailyDigestCallSessionSummary`, `PublisherSession`, `SourceHealth`,
`Quality`, `Percentiles`, `Segments`, `ViewerBehavior`,
`EncodingProfile`, `Incident`, and friends.

## Chat

- **ID-based message pagination** on `getOrCreateChannel` (`ChannelApi`
and `ChatApi`): `messages_id_lt`, `messages_id_lte`, `messages_id_gt`,
`messages_id_gte`, `messages_id_around`.
- **`sendMessage`** gains `include_channel_context` (response carries
`channel_context: ChannelContextResponse` — slim `cid` / `type` / `id` /
`created_by`) and `include_mentioned_members` (per mentioned user,
whether they are currently a channel member; requires
`ReadChannelMembers`).
- **Channel export** gains `format: 'json' | 'csv'` (csv requires
`version=v2`, incompatible with `export_users`) and `include_fields` for
selecting csv message columns.
- `QueryBannedUsersRequest` gains `include_total`; the `user_id` filter
is now documented for client-side use too.

## Feeds

- `AddActivityRequest` / `ActivityRequest` gain `collections:
CollectionRequest[]` — create or update collections in the same call as
the activity; their refs are added to `collection_refs` automatically.

## App settings

- `UpdateAppRequest.member_custom_on_messages_enabled` and
`AppResponseFields.member_custom_on_messages_enabled`.

## Events

- New `moderation.analysis.failed` → `ModerationAnalysisFailedEvent`
(added to the `WSEvent` union).

## ⚠️ Breaking changes

- `AppResponseFields.moderation_flood_rules_enabled` removed.
- `ThreadParticipant.app_pk` removed.
- `ThreadResponse.reply_count` and `ThreadStateResponse.reply_count` are
now required (were optional).
- `MessageRequest.type` drops the `"''"` variant — now `'regular' |
'system'`.
- `CommonApi.getPollOption` no longer accepts a `user_id` query
parameter.

The rest of the models diff is JSDoc that the spec now emits for shared
schema refs (`user`, `channel`, `message`, etc.).

## Verification

- `yarn lint` — clean
- `yarn build` — succeeds