Leave the session you are reading alone, and put its menus on their buttons

Three things about the session screen.

A notification is no longer posted about the session in front of you: the
transcript is already saying it, and one that was posted before you opened
it is cancelled, since a row in the drawer for the conversation on screen
is the same duplication. Bound to RESUMED rather than STARTED, so a session
left on this screen behind another app still reports.

The model and permission menus opened 142px clear of the buttons that
opened them -- the status bar's height, exactly. Compose measures the
anchor in window coordinates, which for an edge-to-edge activity is the
whole display, but asks whether the menu fits inside the visible frame,
which is that less the system bars; sitting just above a control near the
bottom then reads as an overflow and Material3 parks the menu near the
bottom of the visible frame instead. Turning clipping off makes both
questions about the same window.

The model picker now offers "default". The button has always been able to
say it -- that is what a session with no model of its own reads as -- but
the list could not, so choosing any model was a one-way trip. It is the
Claude CLI's own word for "whatever is configured", which its set_model
accepts, so it is a request rather than a name invented here.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

app/androidApp/src/main/kotlin/com/example/aiapp/Notifications.kt

@@ -135,6 +135,10 @@ class NotificationService : Service() {
      * becomes something to clear rather than read.
      */
     private fun show(notification: SessionNotification) {
+        // Nothing to tell somebody about the session they are reading. The transcript in front of
+        // them is already saying it, and a sound over the top of it would be this app announcing
+        // what the screen is showing.
+        if (isOnScreen(notification.sessionId)) return
         val manager = NotificationManagerCompat.from(this)
         // Two different noes, and both are answers rather than faults: the runtime permission
         // refused, and notifications switched off for the app in Android's own settings. Neither
@@ -243,6 +247,35 @@ class NotificationService : Service() {
             )
         }
 
+        /**
+         * The session somebody is looking at, or null when no screen is showing one.
+         *
+         * Process-wide state, which the rest of this app does without: Android constructs the
+         * service and the composition draws the screen, so the two have no common owner a value
+         * could be passed through. [showing] and [stoppedShowing] are the pair, both called from
+         * the one composable that shows a session. Clearing names the session rather than setting
+         * null outright, because moving from one session to another composes the new screen before
+         * the old one's coroutine is cancelled -- an unconditional clear would then throw away the
+         * new screen's claim and start notifying about what is on it.
+         */
+        @Volatile private var onScreen: String? = null
+
+        private fun isOnScreen(sessionId: String) = onScreen == sessionId
+
+        /** Somebody is looking at [sessionId]; nothing is posted about it until they stop. */
+        fun showing(context: Context, sessionId: String) {
+            onScreen = sessionId
+            // Whatever was posted about it before is about to be read, so it has nothing left
+            // to say -- and a row in the drawer for the conversation on screen is the same
+            // duplication this whole rule is about.
+            NotificationManagerCompat.from(context).cancel(sessionId, ALERT_ID)
+        }
+
+        /** They have stopped, unless another screen has claimed it since. */
+        fun stoppedShowing(sessionId: String) {
+            if (onScreen == sessionId) onScreen = null
+        }
+
         private const val ALERT_CHANNEL = "sessions"
         private const val ONGOING_CHANNEL = "connection"
         private const val ONGOING_ID = 1