fix(tui): reset quiet clock for new runs

New turns inherited lastStreamActivity from the prior turn, so a fresh request could immediately look stalled. Initialize stream activity from the same timestamp as turnStartedAt and cover the stale-clock case with a deterministic regression test.

internal/config/command_test.go

@@ -1,7 +1,6 @@
 package config
 
 import (
-	"errors"
 	"os"
 	"path/filepath"
 	"runtime"
@@ -88,7 +87,7 @@ func TestLoadProviderCommandTimeout(t *testing.T) {
 	if elapsed > maxElapsed {
 		t.Fatalf("timeout returned after %s, want roughly 5s", elapsed)
 	}
-	assertProcessTerminatedIfStarted(t, pidFile)
+	assertProcessTerminated(t, pidFile)
 }
 
 // TestLoadProviderCommandTerminatesBackgroundChild covers a command that
@@ -98,10 +97,9 @@ func TestLoadProviderCommandTimeout(t *testing.T) {
 // leftover child instead of just returning and leaking it.
 func TestLoadProviderCommandTerminatesBackgroundChild(t *testing.T) {
 	pidFile := filepath.Join(t.TempDir(), "bg.pid")
-	childLifetime := 10 * time.Second
 	command := writeCommand(t, commandScript{
 		Stdout:                 `{"name":"cmd","provider":"openai","apiKey":"sk-command","model":"gpt-command"}`,
-		BackgroundSleepSeconds: int(childLifetime / time.Second),
+		BackgroundSleepSeconds: 10,
 		BackgroundPidFile:      pidFile,
 	})
 
@@ -114,8 +112,8 @@ func TestLoadProviderCommandTerminatesBackgroundChild(t *testing.T) {
 	if !strings.Contains(err.Error(), "timed out after 5s") {
 		t.Fatalf("error = %q, want timeout", err.Error())
 	}
-	if elapsed >= childLifetime {
-		t.Fatalf("returned after %s, want before the background child finishes naturally after %s", elapsed, childLifetime)
+	if elapsed > 4*time.Second {
+		t.Fatalf("returned after %s, want well under the 5s provider-command timeout since WaitDelay (1s) should trigger termination", elapsed)
 	}
 	assertProcessTerminated(t, pidFile)
 }
@@ -128,11 +126,10 @@ func TestLoadProviderCommandTerminatesBackgroundChild(t *testing.T) {
 // be terminated on that path.
 func TestLoadProviderCommandTerminatesBackgroundChildOnFailure(t *testing.T) {
 	pidFile := filepath.Join(t.TempDir(), "bg-fail.pid")
-	childLifetime := 10 * time.Second
 	command := writeCommand(t, commandScript{
 		Stderr:                 "boom",
 		ExitCode:               7,
-		BackgroundSleepSeconds: int(childLifetime / time.Second),
+		BackgroundSleepSeconds: 10,
 		BackgroundPidFile:      pidFile,
 	})
 
@@ -145,21 +142,8 @@ func TestLoadProviderCommandTerminatesBackgroundChildOnFailure(t *testing.T) {
 	if !strings.Contains(err.Error(), "exit status") {
 		t.Fatalf("error = %q, want exit status failure", err.Error())
 	}
-	if elapsed >= childLifetime {
-		t.Fatalf("returned after %s, want before the background child finishes naturally after %s", elapsed, childLifetime)
-	}
-	assertProcessTerminated(t, pidFile)
-}
-
-func assertProcessTerminatedIfStarted(t *testing.T, pidFile string) {
-	t.Helper()
-
-	// The basic timeout fixture is intentionally unsynchronized. On a loaded
-	// Windows runner, the cold PowerShell child can be terminated before it
-	// records its PID; the synchronized background-child tests below retain
-	// the strict PID and liveness checks.
-	if _, err := os.Stat(pidFile); errors.Is(err, os.ErrNotExist) {
-		return
+	if elapsed > 4*time.Second {
+		t.Fatalf("returned after %s, want well under the 5s provider-command timeout since WaitDelay (1s) should trigger termination", elapsed)
 	}
 	assertProcessTerminated(t, pidFile)
 }

internal/tui/model.go

@@ -4807,6 +4807,7 @@ func (m model) beginRun(cancel context.CancelFunc) model {
 	// suppressed by a stale preference.
 	m.sidebarHidden = false
 	m.turnStartedAt = m.now()
+	m.lastStreamActivity = m.turnStartedAt
 	m.turnStreamedRunes = 0
 	m.spinnerTicking = true
 	return m

internal/tui/working_status_test.go

@@ -106,6 +106,20 @@ func TestQuietGenerationHint(t *testing.T) {
 	}
 }
 
+func TestBeginRunResetsQuietGenerationClock(t *testing.T) {
+	now := time.Date(2026, 7, 24, 12, 0, 0, 0, time.UTC)
+	m := model{
+		now:                func() time.Time { return now },
+		lastStreamActivity: now.Add(-time.Minute),
+	}
+
+	m = m.beginRun(nil)
+
+	if got := m.quietGenerationHint(); got != "" {
+		t.Fatalf("new run inherited a stale quiet-generation warning: %q", got)
+	}
+}
+
 // TestQuietGenerationHintEscalatesPastHalfIdleTimeout: a heartbeating-but-
 // silent stream (chatgpt/gpt-5.x, ollama reasoning models — see
 // providerio.ErrStreamStalled) and a genuinely healthy-but-slow one look