feat(ai-chat): 动态切换输入框 placeholder 文案，支持语音和媒体附件提示

lang/en-us/ai-chat/index.js

@@ -152,6 +152,11 @@ export const lang = {
 	releaseToSend: 'Release to send',
 	releaseToCancel: 'Release to cancel',
 	slideUpToCancel: '↑ Slide up to cancel',
+	slideUpToCancelHint: '↑ Slide up to cancel',
+	// PR-INPUT-PLACEHOLDER-DYNAMIC (2026-09-28): dynamic input placeholder by context
+	placeholderDefault: 'Type a message or hold to talk',
+	placeholderWithAudio: 'Add a note for your voice (optional)',
+	placeholderWithMedia: 'Add a caption (optional)',
 	slideUpToCancelHint: '↑ Release to cancel',
 	voiceStartFailed: 'Cannot start recording',
 	voiceStopFailed: 'Recording failed, please try again',

lang/zh-cn/ai-chat/index.js

@@ -152,6 +152,11 @@ export const lang = {
 	releaseToCancel: '松开取消',
 	slideUpToCancel: '↑ 上滑取消',
 	slideUpToCancelHint: '↑ 松开取消',
+	// PR-INPUT-PLACEHOLDER-DYNAMIC (2026-09-28): 输入框 placeholder 按上下文动态切换
+	//   默认 / 有语音附件 / 有其他媒体附件, 三态文案互不冲突
+	placeholderDefault: '发消息或按住说话',
+	placeholderWithAudio: '给语音留言加个说明（可选）',
+	placeholderWithMedia: '添加文字说明（可选）',
 	voiceStartFailed: '无法开始录音',
 	voiceStopFailed: '录音失败，请重试',
 	voiceNotSupported: '当前平台不支持语音输入',