Branch review pass:
- useWhatsappCallSession: drop unused `error` ref and unused exports
(hasActiveWhatsappCall, isWhatsappCallMuted), fold sendWhatsappCallBeacon
into a private beaconTerminate helper since only sendWhatsappTerminateBeacon
consumed it externally. Trim WHAT-comments; keep WHY-comments
(browser-quirk explanations, race-condition notes, auth-cookie rationale).
- VoiceCall.vue bubble: fix `data || data` short-circuit that did nothing —
upstream key transform was the same on both branches; collapse to one read.
- calls/useCallSession/actionCable/FloatingCallWidget/VoiceCallButton:
drop comments that just describe what the next line already says.
Net diff: -63 lines across 7 files. No behavior change.