v0.1.0 of tickki_chat_flutter

Tickki Chat SDK for Flutter — embed live agent chat into your app with a drop-in widget or headless primitives. Changelog excerpt: - Initial release. - Headless surface: TickkiChatclient with session lifecycle, message send/list, typing/heartbeat, attachment upload, and a private-channel realtime subscription. - Drop-in widget: TickkiChatWidget.show(context, ...)opens a complete branded chat screen, fetching colors and feature flags from /api/v1/chat/config. - Strings are overridable for i18n; colors are dashboard-controlled.