fix: fail closed talk provider selection

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

@@ -68,6 +68,50 @@ class TalkModeConfigParsingTest {
     assertEquals("voice-normalized", selection?.config?.get("voiceId")?.jsonPrimitive?.content)
   }
 
+  @Test
+  fun rejectsNormalizedTalkProviderPayloadWhenProviderMissingFromProviders() {
+    val talk =
+      json.parseToJsonElement(
+          """
+          {
+            "provider": "acme",
+            "providers": {
+              "elevenlabs": {
+                "voiceId": "voice-normalized"
+              }
+            }
+          }
+          """.trimIndent(),
+        )
+        .jsonObject
+
+    val selection = TalkModeManager.selectTalkProviderConfig(talk)
+    assertEquals(null, selection)
+  }
+
+  @Test
+  fun rejectsNormalizedTalkProviderPayloadWhenProviderIsAmbiguous() {
+    val talk =
+      json.parseToJsonElement(
+          """
+          {
+            "providers": {
+              "acme": {
+                "voiceId": "voice-acme"
+              },
+              "elevenlabs": {
+                "voiceId": "voice-normalized"
+              }
+            }
+          }
+          """.trimIndent(),
+        )
+        .jsonObject
+
+    val selection = TalkModeManager.selectTalkProviderConfig(talk)
+    assertEquals(null, selection)
+  }
+
   @Test
   fun fallsBackToLegacyTalkFieldsWhenNormalizedPayloadMissing() {
     val legacyApiKey = "legacy-key" // pragma: allowlist secret