fix(tui): use isBackspace and isEnter helpers in Editor

Fixes Backspace and Enter not working with Caps Lock enabled.
The Kitty protocol sends lock key bits in modifiers which broke
the raw byte detection.

packages/tui/src/components/editor.ts

@@ -8,6 +8,7 @@ import {
 	isArrowLeft,
 	isArrowRight,
 	isArrowUp,
+	isBackspace,
 	isCtrlA,
 	isCtrlC,
 	isCtrlE,
@@ -421,8 +422,8 @@ export class Editor implements Component {
 			// Modifier + Enter = new line
 			this.addNewLine();
 		}
-		// Plain Enter (char code 13 for CR) - only CR submits, LF adds new line
-		else if (data.charCodeAt(0) === 13 && data.length === 1) {
+		// Plain Enter - submit (handles both legacy \r and Kitty protocol with lock bits)
+		else if (isEnter(data)) {
 			// If submit is disabled, do nothing
 			if (this.disableSubmit) {
 				return;
@@ -458,7 +459,7 @@ export class Editor implements Component {
 			}
 		}
 		// Backspace
-		else if (data.charCodeAt(0) === 127 || data.charCodeAt(0) === 8) {
+		else if (isBackspace(data)) {
 			this.handleBackspace();
 		}
 		// Line navigation shortcuts (Home/End keys)