fix(tui): auto-dismiss skill loaded notices after 3 seconds

Transient notices (skill loaded, memory, signal, subagent logs) were
piling up because every new event reset the single expiry sweep timer.
Now each transient notice gets its own 3-second sweep, so expired
notices are pruned independently instead of waiting for a quiet gap.

- Reduce noticeTTL from 5s to 3s.
- Always prune on noticeExpireMsg; drop the stale-sequence guard that
  delayed expiry when newer notices arrived.

Author: jkyberneees

internal/tui/coverage_test.go

@@ -96,7 +96,7 @@ func TestTransientNoticeExpires(t *testing.T) {
 	if got := strings.Join(m.notices, "\n"); got != "sticky" {
 		t.Errorf("notices after expiry = %q", got)
 	}
-	// A stale timer (superseded by a newer notice) must not clear anything.
+	// A stale timer must not clear notices that have not expired yet.
 	m.addTransientNote("skill · saved")
 	m.Update(noticeExpireMsg{seq: m.noticeSeq - 1})
 	if len(m.notices) != 2 {

internal/tui/model.go

@@ -169,9 +169,9 @@ func (a autocomplete) height() int {
 
 // noticeTTL is how long transient info traces (skill / memory / signal /
 // subagent) stay on screen before fading out.
-const noticeTTL = 5 * time.Second
+const noticeTTL = 3 * time.Second
 
-// noticeExpireMsg fires noticeTTL after the last transient notice was added.
+// noticeExpireMsg fires noticeTTL after a transient notice was added.
 type noticeExpireMsg struct {
 	seq int
 }
@@ -287,10 +287,8 @@ func (m *Model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
 		return m.handleEvent(client.Event(msg))
 
 	case noticeExpireMsg:
-		if msg.seq == m.noticeSeq {
-			m.pruneNotices(time.Now())
-			m.refresh()
-		}
+		m.pruneNotices(time.Now())
+		m.refresh()
 		return m, nil
 
 	case tea.MouseMsg: