Webapp: Inbox, search, and knowledge stores

The inbox is now a proper workspace for managing conversations. Search is instant, knowledge stores are here, and the whole app feels smoother.

What's new

• Chat has been renamed to Inbox with filters, assignees, and a real conversation count badge.
• Fast, full-text search across all conversations.
• Knowledge stores with full create, read, update, and delete support.
• A video lightbox with download and copy actions.
• A new motion system for consistent animations and transitions across the app.
• Performance improvements that reduce unnecessary re-renders and network requests.