linetest: waiting_for_quiet needs the full watched window (R-1250)

The live proof found a fresh agent answering waiting before it had watched one minute; a quiet
box's torrent app would be held for nothing.

internal/linetest/linetest.go

@@ -336,6 +336,9 @@ func (t *Tester) WaitingForQuiet() bool {
 	t.mu.Lock()
 	samples := append([]txSample(nil), t.samples...)
 	t.mu.Unlock()
+	if len(samples) < QuietMinutes+1 {
+		return false // not yet watched for 10 minutes (a fresh start): not known to be busy, so no hold
+	}
 	q, _ := quiet(samples)
 	return !q
 }

internal/linetest/linetest_test.go

@@ -549,3 +549,26 @@ func TestQuietBoxIsNotWaiting(t *testing.T) {
 		t.Fatal("ten quiet minutes: the weekly Tick runs; waiting_for_quiet must be false")
 	}
 }
+
+// Live proof 2026-10-24 (demo-hp): a freshly started tester answered waiting_for_quiet before it had watched a single
+// minute, so a quiet box's torrent app would be held for nothing. Waiting needs the full window, seen busy.
+func TestFreshTesterIsNotWaiting(t *testing.T) {
+	r := &rig{run: &fakeRunner{}, gate: &fakeGate{}, now: time.Date(2026, 10, 20, 12, 0, 0, 0, time.UTC), tunnel: true}
+	r.t = New(r.run, func() (netip.Addr, bool) { return netip.MustParseAddr("10.77.0.1"), r.tunnel }, r.gate,
+		func() (uint64, error) { return r.tx, nil }, "host-x", filepath.Join(t.TempDir(), "line-test.json"), nil)
+	r.t.loc = time.UTC
+	r.t.now = func() time.Time { return r.now }
+	if r.t.WaitingForQuiet() {
+		t.Fatal("no minute watched yet: waiting_for_quiet must be false")
+	}
+	for i := 0; i < QuietMinutes; i++ {
+		r.minute(600_000_000)
+	}
+	if r.t.WaitingForQuiet() {
+		t.Fatal("10 samples are 9 minutes: still not a full window")
+	}
+	r.minute(600_000_000)
+	if !r.t.WaitingForQuiet() {
+		t.Fatal("a full busy window: waiting_for_quiet must be true")
+	}
+}