Honor [scheduler] create_cron_data_intervals when serializing cron schedules in the Go SDK

### Background The Go bundle serializer always emits `CronTriggerTimetable` for a cron `schedule`, which only matches the **default** deployment (`[scheduler] create_cron_data_intervals = False`). When a deployment sets it to `True`, Python's `_create_timetable` (`task-sdk/src/airflow/sdk/definitions/dag.py`) produces `CronDataIntervalTimetable` instead, so a Go-authored DAG diverges from the equivalent Python DAG. The Go bundle binary cannot read `airflow.cfg`, so it has no way to branch on the flag today. The relevant scheduler settings must be delivered from the supervisor (Python `ExecutableCoordinator`) to the lang-SDK over the coordinator protocol first. Current hardcoded branch in `go-sdk/pkg/execution/serde.go` (`serializeTimetable`): ```go default: return map[string]any{ "__type": "airflow.timetables.trigger.CronTriggerTimetable", "__var": map[string]any{ "expression": *schedule, "timezone": "UTC", "interval": 0.0, "run_immediately": false, }, } ``` ### What needs to happen 1. Extend the coordinator protocol so the supervisor sends `create_cron_data_intervals` (and `create_delta_data_intervals`, once timedelta schedules are supported) to the bundle — e.g. as fields on `DagFileParseRequest`. 2. In `serializeTimetable`, emit `CronDataIntervalTimetable` (`{expression, timezone}`) when `create_cron_data_intervals` is `True` and `CronTriggerTimetable` when `False`, mirroring `_create_timetable`. 3. Carry the DAG timezone over the same channel; `serializeTimetable` currently hardcodes `"UTC"`. ### Acceptance criteria - A cron-scheduled Go DAG serializes to the same timetable `__type` and `__var` as the equivalent Python DAG under both values of `create_cron_data_intervals`. - DAG timezone is no longer hardcoded to `"UTC"`. - The `TODO` on `serializeTimetable` in `go-sdk/pkg/execution/serde.go` is removed. ### Context - Originating PR: #67155 (Go-SDK Dag/Task specs a…