fix(notifications): prune expired toasts and skip invisible draws

The status-bar notifications only expired the front of the queue, so an
expired newer toast could sit in front of a still-live older one and
hide it from view. The liveness check that drives continuous repaints
also disagreed with what render() actually showed.

- Expired toasts are now pruned wherever they sit in the queue, not just
  at the front, so the newest remaining toast is always a live one.
- The visible toast is the newest live entry, skipping an expired newer
  one. The liveness check reports active while a toast is visible plus
  one trailing frame, so the final faded-out state is painted once and
  then repaints stop; it self-expires if render() is skipped.

Tests: pruning removes expired entries from anywhere in the queue, the
visible toast skips an expired newest entry, and liveness tracks it.

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

src/ui/notifications.cpp

@@ -14,15 +14,15 @@ namespace ui {
 
 void Notifications::render()
 {
-    // Remove expired notifications
-    while (!notifications_.empty() && notifications_.front().isExpired()) {
-        notifications_.pop_front();
-    }
-    
+    // Remove every expired notification; the newest remaining one is then both the last and a live one.
+    pruneExpired(notifications_, std::chrono::steady_clock::now());
+
     if (notifications_.empty()) {
+        last_drawn_ = {};          // nothing painted: the trailing "clean frame" is this one
         return;
     }
-    
+    last_drawn_ = std::chrono::steady_clock::now();
+
     // Only show the most recent (last) notification as a compact status-bar pill
     const auto& notif = notifications_.back();
 

src/ui/notifications.h

@@ -4,6 +4,7 @@
 
 #pragma once
 
+#include <algorithm>
 #include <string>
 #include <deque>
 #include <chrono>
@@ -48,11 +49,10 @@ struct Notification {
         , duration_seconds(duration)
     {}
     
-    bool isExpired() const {
-        auto now = std::chrono::steady_clock::now();
-        auto elapsed = std::chrono::duration<float>(now - created_at).count();
-        return elapsed >= duration_seconds;
+    bool isExpiredAt(std::chrono::steady_clock::time_point now) const {
+        return std::chrono::duration<float>(now - created_at).count() >= duration_seconds;
     }
+    bool isExpired() const { return isExpiredAt(std::chrono::steady_clock::now()); }
     
     float getProgress() const {
         auto now = std::chrono::steady_clock::now();
@@ -144,12 +144,27 @@ public:
     
     void render();
 
-    /// @brief Check if there are non-expired notifications (needs continuous frames for animation)
+    /// Drops every expired entry (not just the front: an expired back entry hid a still-live older toast).
+    static void pruneExpired(std::deque<Notification>& q, std::chrono::steady_clock::time_point now) {
+        q.erase(std::remove_if(q.begin(), q.end(),
+                               [&](const Notification& n) { return n.isExpiredAt(now); }), q.end());
+    }
+
+    /// The toast render() shows: the newest live one (nullptr when none).
+    const Notification* visibleToast() const {
+        const auto now = std::chrono::steady_clock::now();
+        for (auto it = notifications_.rbegin(); it != notifications_.rend(); ++it)
+            if (!it->isExpiredAt(now)) return &*it;
+        return nullptr;
+    }
+
+    /// @brief True while a toast is visible, plus one trailing frame after it disappears (so the
+    /// final, fully-faded state is actually painted). hasActive() now implies a visible pill.
     bool hasActive() const {
-        for (const auto& n : notifications_) {
-            if (!n.isExpired()) return true;
-        }
-        return false;
+        if (visibleToast()) return true;
+        using namespace std::chrono;
+        return last_drawn_ != steady_clock::time_point{} &&
+               steady_clock::now() - last_drawn_ < milliseconds(250);   // self-expires if render() is skipped
     }
     
     void clear() {
@@ -177,6 +192,7 @@ private:
 
     std::deque<Notification> notifications_;
     size_t max_notifications_ = 5;
+    std::chrono::steady_clock::time_point last_drawn_{};
     std::function<void(const std::string&, bool)> console_callback_;
 
     std::deque<AlertRecord> history_;