Inbox overhaul, AI assistant config, and iOS catches up

Resolved tab in the sidebar, configurable AI assistant, and full conversation management on iOS.

• Dedicated Resolved tab keeps closed threads out of the active inbox
• Drag to reorder sidebar items
• Command bar defaults to "All" scope with contact search built in
• Keyboard shortcuts moved to Option+1-5 to avoid browser conflicts
• AI assistant configurable per org: custom name, greeting, instructions, personality
• Toggle AI assistant on or off from settings

iOS

• AI assistant with streaming responses
• Knowledge store management and org settings
• Conversation assignment, resolution, and starring via swipe actions
• Widget auto-scrolls new messages and supports rich text