[ENG-4127] feat(connectwise): Communication items

[Cobalt0s]

Description

Add description on contacts communication items.

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ENG-4127

[Cobalt0s]

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• [ENG-4127] feat(connectwise): Communication items #654 👈 (View in Graphite)
• [ENG-4125] feat(connectwise): Custom fields, Communication Items #653
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[anushat05]

I took a pass at the ConnectWise docs and put my changes on a separate branch so it's easy to diff here. Didn't push to your branch directly, if you like it, pull it in.

Main feedback: the page was pitched a layer too low, more like an API reference than a builder guide. I made it short, naming convention plus one example, no raw API payloads and trimmed both ConnectWise sections to match.

• Custom Fields: kept the customField<ID> + mapToName explanation, the read example, and the CW-specific notes (only send what you're changing, null to clear, find the ID in a read response). Dropped the mappedFields block and the separate create/PUT/PATCH payloads.
• Communication Items: leads with the field table and how to map; trimmed the PUT-vs-PATCH narrative and defaultFlag/array-index detail; moved raw JSON Patch into a small "Advanced" note.

Three things to confirm before merge:

1. The communications-items write section says "an update changes only the fields you send." That's the target behavior but the current code still full-replaces on a flat update, so this should land with the partial-update fix, not before.
2. I removed the "removing a default auto-promotes another item" claim since I don't think we verified it. Add it back if you have.
3. I kept the AMPERSAND- field names since that's what builders type, just flagging it's a conscious call to expose that prefix.