Typing Indicator

The logic for the typing indicator resides within src/components/main/compose/messages/mod.rs, src/iui_kit/textarea.rs, and src/ui_kit/src/typing_indicator/mod.rs.

The sending and receiving sides (referred to as local and remote in the diagram) maintain their own state machines. The local side uses its state machine to determine when to send a Typing event (tracks the time since the last key press and periodically re-sends Typing events to prevent the remote side from timing out). The remote side uses its state machine to determine when to display the typing indicator (allows the typing indicator to be automatically removed after a timeout).