JobNimbus source connector missing `source` and `source_name` fields

### Connector Name

source-jobnimbus

### Connector Version

0.0.42 (latest as of Jan 2026)

### What step the error happened?

None

### Relevant information

## Connector
source-jobnimbus

## Problem
The JobNimbus connector does not return the `source` (lead source ID) and `source_name` (lead source name) fields, despite these being standard documented fields in the JobNimbus API.

API Documentation reference: https://documenter.getpostman.com/view/3919598/S11PpG4x

The contacts endpoint documentation explicitly lists:
- `source` - "The lead source id for this record" (integer)
- `source_name` - "The lead source name for this record" (text)

These fields are visible in the JobNimbus UI and critical for marketing attribution reporting.

## Expected behavior
The contacts stream should include `source` and `source_name` fields.

## Connector version
0.0.42 (latest as of Jan 2026)

### Relevant log output

```shell

```

### Contribute

- [ ] Yes, I want to contribute

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**Internal Tracking:** https://github.com/airbytehq/oncall/issues/10944