refactor(app): extract reconnect-chime edge triggers + unit tests

Pull the PeerConnecting/PeerConnected chime logic out of update()'s match
arms into two pure functions — reconnect_attempt_chime and reconnected_chime
— that own the connecting/ever_connected set transitions and return the
Option<Sound> to play, leaving the notify::play side effect in update.
Behavior-preserving; the full suite still passes.

Adds 4 #[cfg(test)] tests pinning the edge-trigger contract: a first dial is
silent, a reconnect attempt chimes exactly once and stays silent across the
supervisor's repeated redials, "reconnected" only fires after a prior link,
and a two-outage cycle chimes attempt->reconnected each time (per-outage, not
once-ever). Closes the last catalogued Tier B test gap.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/app/mod.rs

@@ -179,6 +179,38 @@ fn subscription(_state: &AppState) -> Subscription<AppMessage> {
     Subscription::batch(vec![core_sub, event_sub])
 }
 
+/// Reconnect-chime edge trigger for `UiEvent::PeerConnecting`. Marks the peer as
+/// connecting and returns `Some(Sound::ReconnectAttempt)` exactly once per outage:
+/// only when the peer had a live link before (a genuine reconnect, not a first
+/// dial) AND we weren't already in the connecting state (so the supervisor's
+/// repeated redials while still down don't re-chime). Pure so the once-per-
+/// disconnect behavior is unit-testable without a GUI or audio.
+fn reconnect_attempt_chime(
+    connecting: &mut HashSet<EndpointId>,
+    ever_connected: &HashSet<EndpointId>,
+    id: EndpointId,
+) -> Option<Sound> {
+    let is_reconnect_attempt = ever_connected.contains(&id);
+    let was_already_connecting = connecting.contains(&id);
+    connecting.insert(id);
+    (is_reconnect_attempt && !was_already_connecting).then_some(Sound::ReconnectAttempt)
+}
+
+/// Reconnect-chime edge trigger for `UiEvent::PeerConnected`. Clears the connecting
+/// state, records that we've linked with this peer at least once, and returns
+/// `Some(Sound::Reconnected)` only if it had connected before (a true reconnect, not
+/// the first link). Pure so the logic is unit-testable.
+fn reconnected_chime(
+    connecting: &mut HashSet<EndpointId>,
+    ever_connected: &mut HashSet<EndpointId>,
+    id: EndpointId,
+) -> Option<Sound> {
+    let was_reconnect = ever_connected.contains(&id);
+    connecting.remove(&id);
+    ever_connected.insert(id);
+    was_reconnect.then_some(Sound::Reconnected)
+}
+
 fn update(state: &mut AppState, message: AppMessage) -> Task<AppMessage> {
     match message {
         AppMessage::NicknameChanged(val) => {
@@ -267,19 +299,17 @@ fn update(state: &mut AppState, message: AppMessage) -> Task<AppMessage> {
                     state.peers.insert(id, peer_state);
                 }
                 UiEvent::PeerConnecting { id } => {
-                    let is_reconnect_attempt = state.ever_connected.contains(&id);
-                    let was_already_connecting = state.connecting.contains(&id);
-                    state.connecting.insert(id);
-                    if is_reconnect_attempt && !was_already_connecting {
-                        notify::play(Sound::ReconnectAttempt, state.config.custom_sound_reconnect_attempt.as_deref());
+                    if let Some(sound) =
+                        reconnect_attempt_chime(&mut state.connecting, &state.ever_connected, id)
+                    {
+                        notify::play(sound, state.config.custom_sound_reconnect_attempt.as_deref());
                     }
                 }
                 UiEvent::PeerConnected { id } => {
-                    let was_reconnect = state.ever_connected.contains(&id);
-                    state.connecting.remove(&id);
-                    state.ever_connected.insert(id);
-                    if was_reconnect {
-                        notify::play(Sound::Reconnected, state.config.custom_sound_reconnected.as_deref());
+                    if let Some(sound) =
+                        reconnected_chime(&mut state.connecting, &mut state.ever_connected, id)
+                    {
+                        notify::play(sound, state.config.custom_sound_reconnected.as_deref());
                     }
                 }
                 UiEvent::AudioLevels(levels) => {
@@ -884,3 +914,84 @@ fn view(state: &AppState) -> Element<'_, AppMessage> {
         .into()
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::{reconnect_attempt_chime, reconnected_chime};
+    use crate::notify::Sound;
+    use iroh::EndpointId;
+    use std::collections::HashSet;
+
+    /// A distinct, real `EndpointId` (via the same path the network tests use).
+    fn id() -> EndpointId {
+        iroh::EndpointAddr::from(iroh::SecretKey::generate().public()).id
+    }
+
+    #[test]
+    fn first_dial_does_not_chime() {
+        let mut connecting = HashSet::new();
+        let ever = HashSet::new(); // never connected
+        let peer = id();
+        // A peer we've never linked with is just an initial connect, not a reconnect.
+        assert_eq!(reconnect_attempt_chime(&mut connecting, &ever, peer), None);
+        assert!(connecting.contains(&peer)); // but it is now marked connecting
+    }
+
+    #[test]
+    fn first_connected_does_not_chime() {
+        let mut connecting = HashSet::from([id()]);
+        let mut ever = HashSet::new();
+        let peer = id();
+        connecting.insert(peer);
+        // First successful link: record it, but no "reconnected" chime.
+        assert_eq!(reconnected_chime(&mut connecting, &mut ever, peer), None);
+        assert!(ever.contains(&peer));
+        assert!(!connecting.contains(&peer)); // connecting state cleared
+    }
+
+    #[test]
+    fn reconnect_attempt_chimes_once_then_stays_silent_on_redials() {
+        let peer = id();
+        let mut connecting = HashSet::new();
+        let ever = HashSet::from([peer]); // previously connected
+
+        // First drop → one ReconnectAttempt chime.
+        assert_eq!(
+            reconnect_attempt_chime(&mut connecting, &ever, peer),
+            Some(Sound::ReconnectAttempt)
+        );
+        // The supervisor redials repeatedly while still down — must NOT re-chime.
+        assert_eq!(reconnect_attempt_chime(&mut connecting, &ever, peer), None);
+        assert_eq!(reconnect_attempt_chime(&mut connecting, &ever, peer), None);
+    }
+
+    #[test]
+    fn full_outage_cycle_chimes_attempt_then_reconnected_each_time() {
+        let peer = id();
+        let mut connecting = HashSet::new();
+        let mut ever = HashSet::new();
+
+        // Initial connect: silent, records the peer.
+        assert_eq!(reconnected_chime(&mut connecting, &mut ever, peer), None);
+
+        // Outage 1: attempt chimes once, recovery chimes "reconnected".
+        assert_eq!(
+            reconnect_attempt_chime(&mut connecting, &ever, peer),
+            Some(Sound::ReconnectAttempt)
+        );
+        assert_eq!(
+            reconnected_chime(&mut connecting, &mut ever, peer),
+            Some(Sound::Reconnected)
+        );
+
+        // Outage 2: a fresh disconnect chimes again (per-outage, not once-ever).
+        assert_eq!(
+            reconnect_attempt_chime(&mut connecting, &ever, peer),
+            Some(Sound::ReconnectAttempt)
+        );
+        assert_eq!(
+            reconnected_chime(&mut connecting, &mut ever, peer),
+            Some(Sound::Reconnected)
+        );
+    }
+}