test(tui-04): assert single-consumer contract for ws.messages and ws.connection

apps/tui/src/main/kotlin/com/correx/apps/tui/TuiApp.kt

@@ -61,6 +61,10 @@ fun main(args: Array<String>) {
                 }
             }
 
+            // IMPORTANT: ws.messages and ws.connection are single-consumer cold flows
+            // (Channel.UNLIMITED.receiveAsFlow). Do not add a second collector for either —
+            // events would be split across collectors and dropped from the dispatcher's view.
+            // If a second consumer is needed (e.g. metrics), share via a downstream broadcast.
             effectScope.launch {
                 ws.messages.collect { msg ->
                     runner.runOnRenderThread { dispatch(Action.ServerEventReceived(msg)) }

apps/tui/src/test/kotlin/com/correx/apps/tui/SingleConsumerContractTest.kt

@@ -0,0 +1,29 @@
+package com.correx.apps.tui
+
+import org.junit.jupiter.api.Assertions.assertEquals
+import org.junit.jupiter.api.Test
+import java.io.File
+
+class SingleConsumerContractTest {
+
+    private val sourceRoot = File("src/main/kotlin")
+
+    private fun countOccurrences(literal: String): Int =
+        sourceRoot.walkTopDown()
+            .filter { it.isFile && it.extension == "kt" }
+            .sumOf { file ->
+                file.readText().split(literal).size - 1
+            }
+
+    @Test
+    fun `ws messages has exactly one collector`() {
+        assertEquals(1, countOccurrences("ws.messages.collect"),
+            "Expected exactly one ws.messages.collect in src/main/kotlin")
+    }
+
+    @Test
+    fun `ws connection has exactly one collector`() {
+        assertEquals(1, countOccurrences("ws.connection.collect"),
+            "Expected exactly one ws.connection.collect in src/main/kotlin")
+    }
+}