iOS: Native integrations and conversation management

The iOS app now plugs into Calendar, Reminders, and Mail, and gives you full control over conversation workflows.

What's new

• Native Calendar, Reminders, and Mail integrations built with iOS frameworks.
• Assign conversations to team members and update their status or star them for quick access.
• A conversation management sheet that puts all actions in one place.
• Video thumbnail generation and an audio preview overlay for voice messages.
• Various UI tweaks including toggle menus and email fallback when a user name is missing.