Fix terminal rendering and add improvements

- Enable bracketed paste mode for handling large pastes
- Fix editor duplicate line rendering bug at terminal width
- Add padding support to Markdown component (paddingX/Y)
- Add Spacer component for vertical spacing
- Update chat-simple with spacers between messages

packages/tui/test/virtual-terminal.ts

@@ -32,10 +32,13 @@ export class VirtualTerminal implements Terminal {
 	start(onInput: (data: string) => void, onResize: () => void): void {
 		this.inputHandler = onInput;
 		this.resizeHandler = onResize;
-		// No need for raw mode in virtual terminal
+		// Enable bracketed paste mode for consistency with ProcessTerminal
+		this.xterm.write("\x1b[?2004h");
 	}
 
 	stop(): void {
+		// Disable bracketed paste mode
+		this.xterm.write("\x1b[?2004l");
 		this.inputHandler = undefined;
 		this.resizeHandler = undefined;
 	}