fix(speech): convert base64 TTS data URI before playback per platform

后端 TTS 以 data: URI 返回 base64 mp3(生产实证为合法 LAME mp3),但
App-Plus 的 InnerAudioContext 不支持 data: URI,iOS Safari/微信 webview
也常静默失败,统一报"语音播放失败"。播放前按平台转换:H5 转 Blob URL,
App 端经 plus.io 落 _doc/ 临时文件后播放 file:// 路径,播完清理;Blob 不可
用时退回原始 data: URI。竞态守卫与缓存语义保持不变,158 单测全绿。

mobile-uni/src/services/speech.ts

@@ -2,6 +2,7 @@ import type { AsrResponse, PracticeTtsContext, SpeechPlaybackStatus, SpeechSelec
 import { apiRequest, apiUrl, authHeaders, readTextPayload } from './api';
 import { getAuth } from './auth';
 import type { SpeechCapture } from './speech-capture';
+import { dataUriToBlobUrl, hasNativeAudioFileSupport, isDataAudioUri, removeNativeTempAudio, writeNativeTempAudio } from './speech-audio-source';
 import { applyTtsVoicePreference, getTtsDialectPreference, getTtsVoicePreference } from './tts-voice-preference';
 
 const audioExtensions = ['.mp3', '.wav', '.m4a', '.webm', '.aac', '.ogg'];
@@ -202,26 +203,69 @@ export const createSpeechPlaybackController = (
   };
 
   const playAudioSource = (key: string, source: string, cacheKey: string, currentGeneration: number) => {
-    const context = uni.createInnerAudioContext();
-    audio = context;
-    const isCurrent = () => currentGeneration === generation && audio === context && activeKey === key;
-    context.onPlay(() => {
-      if (isCurrent()) publish(key, 'playing');
-    });
-    context.onEnded(() => {
-      if (isCurrent()) stop();
-    });
-    context.onStop(() => {
-      if (isCurrent()) publish();
-    });
-    context.onError(() => {
-      if (!isCurrent()) return;
+    const isActivePlayback = () => currentGeneration === generation && activeKey === key;
+    const failPlayback = () => {
+      if (!isActivePlayback()) return;
       sourceCache.delete(cacheKey);
       stop();
       onError('语音播放失败，请稍后重试');
-    });
-    context.src = source;
-    context.play();
+    };
+    const startPlayback = (src: string, cleanup?: () => void) => {
+      const context = uni.createInnerAudioContext();
+      audio = context;
+      const isCurrent = () => currentGeneration === generation && audio === context && activeKey === key;
+      const finish = () => {
+        if (cleanup) cleanup();
+      };
+      context.onPlay(() => {
+        if (isCurrent()) publish(key, 'playing');
+      });
+      context.onEnded(() => {
+        if (isCurrent()) {
+          finish();
+          stop();
+        }
+      });
+      context.onStop(() => {
+        if (isCurrent()) {
+          finish();
+          publish();
+        }
+      });
+      context.onError(() => {
+        if (!isCurrent()) return;
+        finish();
+        failPlayback();
+      });
+      context.src = src;
+      context.play();
+    };
+
+    // 后端 TTS 返回 data: URI base64;App-Plus 不支持 data: URI,iOS Safari/微信
+    // webview 也常静默失败,统一先转换:H5 转 Blob URL,App 端落临时文件。
+    if (isDataAudioUri(source)) {
+      if (hasNativeAudioFileSupport()) {
+        void writeNativeTempAudio(source).then((fileUrl) => {
+          if (!fileUrl) {
+            failPlayback();
+            return;
+          }
+          if (!isActivePlayback()) {
+            removeNativeTempAudio(fileUrl);
+            return;
+          }
+          startPlayback(fileUrl, () => removeNativeTempAudio(fileUrl));
+        });
+        return;
+      }
+      const blobUrl = dataUriToBlobUrl(source);
+      if (blobUrl) {
+        startPlayback(blobUrl, () => URL.revokeObjectURL(blobUrl));
+        return;
+      }
+      // Blob 不可用时退回原始 data: URI(桌面 Chrome 等环境可直接播放)
+    }
+    startPlayback(source);
   };
 
   const toggle = async (key: string, text: string, voiceProfile?: SpeechVoiceProfile, practiceContext?: PracticeTtsContext) => {