Put the reply composer at the bottom of the conversation card so the
timeline and composer form one viewport-height panel; the send button is
visible on load and Ctrl/Cmd+Enter submits. Internal notes now open in a
dialog instead of expanding inline, so the sidebar no longer grows.
Remove the shared ticket_composer helper and the inline note expansion CSS;
both dialogs share ticket_dialog_head.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>