fix: 修复 Ctrl+Enter 在标准终端中应插入换行而非发送消息

- parse-keypress.ts: \n (LF) 字节标记为 ctrl=true，因为标准终端中
  Ctrl+Enter 发送 \n，需与普通 Enter (\r) 区分
- defaultBindings.ts: 新增 ctrl+enter -> chat:newline 快捷键绑定，
  支持 Kitty 键盘协议终端（如 Windows Terminal 1.25+）

Co-Authored-By: Sonnet-4.6-CoStrict <noreply@anthropic.com>

packages/@ant/ink/src/core/parse-keypress.ts

@@ -697,12 +697,17 @@ function parseKeypress(s: string = ''): ParsedKey {
     return createNavKey(s, 'mouse', false)
   }
 
-  if (s === '\r' || s === '\r\n') {
+  if (s === '\r\n') {
+    key.raw = undefined
+    key.name = 'return'
+    key.ctrl = true
+  } else if (s === '\r') {
     key.raw = undefined
     key.name = 'return'
   } else if (s === '\n') {
     key.raw = undefined
     key.name = 'return'
+    key.ctrl = true
   } else if (s === '\t') {
     key.name = 'tab'
   } else if (s === '\b' || s === '\x1b\b') {

src/keybindings/defaultBindings.ts

@@ -71,6 +71,9 @@ export const DEFAULT_BINDINGS: KeybindingBlock[] = [
       'meta+o': 'chat:fastMode',
       'meta+t': 'chat:thinkingToggle',
       enter: 'chat:submit',
+      // Ctrl+Enter inserts a newline (Kitty keyboard protocol terminals only;
+      // standard terminals cannot distinguish ctrl+enter from plain enter).
+      'ctrl+enter': 'chat:newline',
       up: 'history:previous',
       down: 'history:next',
       // Editing shortcuts (defined here, migration in progress)