Reject malformed stream batches before mutating the playback queue

tools/chatgui-android/app/src/test/java/com/utun/chat/data/StreamReadQueueTest.kt

@@ -52,4 +52,23 @@ class StreamReadQueueTest {
         assertArrayEquals(audio, queue.take(video = false, audio = true))
         assertArrayEquals(video, queue.take(video = true, audio = false))
     }
+
+    @Test fun malformedTailCannotApplyItsEarlierGapOrReplacePendingData() {
+        val queue = StreamReadQueue(); val original = record(1, 42)
+        queue.add(original)
+        for (invalid in listOf(record(3) + byteArrayOf(1), record(6) + record(9),
+            record(2) + record(1).also { ByteBuffer.wrap(it).putInt(16, 100) })) {
+            assertThrows(IllegalStateException::class.java) { queue.add(invalid) }
+            assertEquals(1, queue.size)
+        }
+        assertArrayEquals(original, queue.take(video = true, audio = true))
+    }
+
+    @Test fun excessiveRecordCountIsRejectedBeforeAnyChange() {
+        val queue = StreamReadQueue(); val original = record(2, 123)
+        queue.add(original)
+        val invalid = List(17) { record(3) }.fold(byteArrayOf()) { bytes, next -> bytes + next }
+        assertThrows(IllegalStateException::class.java) { queue.add(invalid) }
+        assertEquals(1, queue.size); assertArrayEquals(original, queue.take(video = true, audio = true))
+    }
 }