history server event log should capture scheduler id

**Is your feature request related to a problem or challenge? Please describe what you are trying to do.**

at the moment event logs are written in local directory, so associating logs with scheduler is not hard task, if we ship logs to a centralised location (s3 bucket) being able to associate logs with schedulers would help with diagnostics. current assumption is that shipping event logs to s3 would be done by external process

**Describe the solution you'd like**

add additional field to `JobStart` event, like `scheduler_id`

change from

```json
{
"ev": "JobStart",
"version": 1,
"data": {
"job_id": "0382W17Y0G000",
"job_name": "Query derived from TPC-H q1",
"queued_at": 1788250553353,
"submitted_at": 1788250553364,
```
to

```json
{
"ev": "JobStart",
"version": 1,
"data": {
"job_id": "0382W17Y0G000",
"job_name": "Query derived from TPC-H q1",
"queued_at": 1788250553353,
"submitted_at": 1788250553364,
"scheduler_id" : "< random scheduler id >"
```

**Describe alternatives you've considered**

alternative would be to have a path prefix per scheduler id, which at the moment we cant retrieve from available apis

```bash
curl http://localhost:50050/api/state
{"started":1788384057783,"version":"54.0.0","datafusion_version":"55.0.0","substrait_support":false,"keda_support":false,"prometheus_support":false,"graphviz_support":false,"spark_support":false,"scheduling_policy":"push-staged","enable_embedded_flight_proxy":false}%
```

**Additional context**

we do not have scheduler id associated with the scheduler, so we might need to add it

Start by tracing the JobStart event and the scheduler state exposed by the /api/state endpoint. Determine where a scheduler identity can be created and how the event log is serialized; done means JobStart records that identity consistently and the resulting event can associate centralized logs with a scheduler.

Written by the indexing model from the issue text.