feat(ui): add New Chat to History (#1124)

app/src/main/java/com/m57/hermescontrol/NavigationController.kt

@@ -12,6 +12,10 @@ data class PendingChatNavigation(
     val requestId: Long,
 )
 
+data class PendingNewChatNavigation(
+    val requestId: Long,
+)
+
 /**
  * Central navigation controller with deduplication guard.
  *
@@ -27,9 +31,12 @@ object NavigationController {
     var backStack: NavBackStack<NavKey>? = null
     var pendingChatNavigation: PendingChatNavigation? by mutableStateOf(null)
         private set
+    var pendingNewChatNavigation: PendingNewChatNavigation? by mutableStateOf(null)
+        private set
     val pendingSessionId: String? get() = pendingChatNavigation?.sessionId
 
     private var nextChatNavigationRequestId = 0L
+    private var nextNewChatNavigationRequestId = 0L
 
     /**
      * Top-level primary screens (all drawer-accessible screens).
@@ -73,6 +80,14 @@ object NavigationController {
         queueChatNavigation(sessionId, scrollToBottom = true)
     }
 
+    fun openNewChat() {
+        pendingNewChatNavigation =
+            PendingNewChatNavigation(
+                requestId = ++nextNewChatNavigationRequestId,
+            )
+        navigateTo(ChatScreen)
+    }
+
     private fun queueChatNavigation(
         sessionId: String,
         scrollToBottom: Boolean,
@@ -90,6 +105,9 @@ object NavigationController {
     fun consumePendingChatNavigation(): PendingChatNavigation? =
         pendingChatNavigation.also { pendingChatNavigation = null }
 
+    fun consumePendingNewChatNavigation(): PendingNewChatNavigation? =
+        pendingNewChatNavigation.also { pendingNewChatNavigation = null }
+
     fun consumePendingSessionId(): String? = consumePendingChatNavigation()?.sessionId
 
     /** Clear the stack and navigate to the given screen atomically. */

app/src/main/java/com/m57/hermescontrol/ui/chat/components/ChatLifecycleEffects.kt

@@ -45,9 +45,15 @@ fun ChatLifecycleEffects(
 
     // Switch to session from notification/history
     val pendingNavigation = NavigationController.pendingChatNavigation
-    LaunchedEffect(sessionId, pendingNavigation, connectionStatus) {
+    val pendingNewChatNavigation = NavigationController.pendingNewChatNavigation
+    LaunchedEffect(sessionId, pendingNavigation, pendingNewChatNavigation, connectionStatus) {
         if (connectionStatus != ConnectionStatus.CONNECTED) return@LaunchedEffect
+        val newChatRequest = NavigationController.consumePendingNewChatNavigation()
         val request = NavigationController.consumePendingChatNavigation()
+        if (newChatRequest != null) {
+            viewModel.createNewSession()
+            return@LaunchedEffect
+        }
         val target = request?.sessionId ?: sessionId
         if (!target.isNullOrBlank()) {
             viewModel.switchSession(target)

app/src/main/java/com/m57/hermescontrol/ui/sessions/SessionsScreen.kt

@@ -34,6 +34,7 @@ import androidx.compose.material.icons.Icons
 import androidx.compose.material.icons.automirrored.filled.CallSplit
 import androidx.compose.material.icons.automirrored.filled.KeyboardArrowRight
 import androidx.compose.material.icons.automirrored.filled.Send
+import androidx.compose.material.icons.filled.Add
 import androidx.compose.material.icons.filled.CheckCircle
 import androidx.compose.material.icons.filled.Close
 import androidx.compose.material.icons.filled.Code
@@ -466,6 +467,15 @@ fun SessionsScreen(
         isRefreshing = state.isLoading,
         onRefresh = { viewModel.loadSessions() },
         actions = {
+            IconButton(
+                onClick = { NavigationController.openNewChat() },
+                modifier = Modifier.testTag("sessions_action_new_chat"),
+            ) {
+                Icon(
+                    imageVector = Icons.Filled.Add,
+                    contentDescription = stringResource(R.string.content_desc_new_chat),
+                )
+            }
             if (state.hasHiddenSessions) {
                 IconButton(
                     onClick = { viewModel.toggleShowHidden() },

app/src/test/java/com/m57/hermescontrol/NavigationControllerTest.kt

@@ -5,6 +5,7 @@ import androidx.navigation3.runtime.NavKey
 import org.junit.After
 import org.junit.Assert.assertEquals
 import org.junit.Assert.assertFalse
+import org.junit.Assert.assertNotNull
 import org.junit.Assert.assertNull
 import org.junit.Assert.assertTrue
 import org.junit.Before
@@ -21,12 +22,14 @@ class NavigationControllerTest {
         // Start fresh — no pinned back stack from a previous test
         NavigationController.backStack = null
         NavigationController.consumePendingSessionId()
+        NavigationController.consumePendingNewChatNavigation()
     }
 
     @After
     fun tearDown() {
         NavigationController.backStack = null
         NavigationController.consumePendingSessionId()
+        NavigationController.consumePendingNewChatNavigation()
     }
 
     // ── Dedup guard: navigateTo with same key ──────────────────────────────
@@ -119,6 +122,18 @@ class NavigationControllerTest {
         assertNull(NavigationController.consumePendingSessionId())
     }
 
+    @Test
+    fun `openNewChat navigates to chat and exposes a consumable request`() {
+        val backStack = NavBackStack<NavKey>(HistoryScreen)
+        NavigationController.backStack = backStack
+
+        NavigationController.openNewChat()
+
+        assertEquals(ChatScreen, backStack.lastOrNull())
+        assertNotNull(NavigationController.consumePendingNewChatNavigation())
+        assertNull(NavigationController.consumePendingNewChatNavigation())
+    }
+
     @Test
     fun `openChatSession ignores blank ids`() {
         val backStack = NavBackStack<NavKey>(HistoryScreen)