Avoid holding mutex while waking main loop on wait unblock

Sending to serverInputChan while holding t.mutex could deadlock: if the
channel fills, the send blocks with the mutex held while the main loop
waits on the same mutex and can't drain the channel.

Capture the wake-up need under the lock, send after releasing it.

src/terminal.go

@@ -1882,14 +1882,13 @@ func (t *Terminal) UpdateList(result MatchResult) {
 	merger := result.merger
 	t.mutex.Lock()
 	waitWasBlocked := t.waitBlocked
+	wakeUp := false
 	if result.final() {
 		t.searchInProgress = false
 		// If waiting, unblock so main loop can execute pending actions
 		if t.waitBlocked {
 			t.unblockWait()
-			if len(t.pendingActions) > 0 {
+			wakeUp = len(t.pendingActions) > 0
-				t.serverInputChan <- []*action{{t: actIgnore}}
-			}
 		}
 	}
 	prevIndex := minItem.Index()
@@ -2060,6 +2059,13 @@ func (t *Terminal) UpdateList(result MatchResult) {
 	updatePrompt := (trackWasBlocked && !t.trackBlocked) || (waitWasBlocked && !t.waitBlocked)
 	t.mutex.Unlock()
 
+	// Wake up the main loop to execute pending actions after wait unblocks.
+	// Send after releasing the mutex to avoid blocking on a full channel
+	// while holding it.
+	if wakeUp {
+		t.serverInputChan <- []*action{{t: actIgnore}}
+	}
+
 	t.reqBox.Set(reqInfo, nil)
 	if updateList {
 		t.reqBox.Set(reqList, nil)