docs: Add FreeBSD build instructions and current status (#33617)

This adds documentation for building Zed on FreeBSD.
Notice WebRTC/LiveKit remains unsupported on this platform for now.

Follow-up to:
- #33162
- #30981

Release Notes:

- N/A

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Co-authored-by: Peter Tripp <peter@zed.dev>
351ba5023bG36maid committed on 7/1/2025, 3:18:34 PM· committed by GitHubparent3041de0
1 file changedLine totals unavailable