fix(android): fall back on legacy talk errors

apps/android/app/src/main/java/ai/openclaw/app/voice/TalkSpeakClient.kt

@@ -41,7 +41,7 @@ internal class TalkSpeakClient(
     if (!response.ok) {
       val error = response.error
       val message = error?.message ?: "talk.speak request failed"
-      return if (isFallbackEligible(error?.details?.reason)) {
+      return if (isFallbackEligible(error)) {
         TalkSpeakResult.FallbackToLocal(message)
       } else {
         TalkSpeakResult.Failure(message)
@@ -74,7 +74,9 @@ internal class TalkSpeakClient(
     )
   }
 
-  private fun isFallbackEligible(reason: String?): Boolean {
+  private fun isFallbackEligible(error: GatewaySession.ErrorShape?): Boolean {
+    val reason = error?.details?.reason
+    if (reason == null) return true
     return reason == "talk_unconfigured" ||
       reason == "talk_provider_unsupported" ||
       reason == "method_unavailable"

apps/android/app/src/test/java/ai/openclaw/app/voice/TalkSpeakClientTest.kt

@@ -103,4 +103,26 @@ class TalkSpeakClientTest {
     val result = client.synthesize(text = "Hello", directive = null)
     assertTrue(result is TalkSpeakResult.Failure)
   }
+
+  @Test
+  fun fallsBackWhenGatewayOmitsReason() = runTest {
+    val client =
+      TalkSpeakClient(
+        requestDetailed = { _, _, _ ->
+          GatewaySession.RpcResult(
+            ok = false,
+            payloadJson = null,
+            error =
+              GatewaySession.ErrorShape(
+                code = "INVALID_REQUEST",
+                message = "unknown method: talk.speak",
+                details = null,
+              ),
+          )
+        },
+      )
+
+    val result = client.synthesize(text = "Hello", directive = null)
+    assertTrue(result is TalkSpeakResult.FallbackToLocal)
+  }
 }