Scanner status tests no longer depend on a 100 ms timer (closes #124)

The two status-send tests now call the send directly on a channel nobody
receives from, so a blocking send hangs the test into its timeout instead
of racing a 100 ms timer that a loaded host can miss.

The gpg test for a child holding gpg's output had the same problem: its
100 ms deadline could fire before the fake gpg wrote the PID of sleep,
and the cleanup then failed. The fake gpg now writes that PID to a named
pipe, and the test cancels only after reading it. It then waits up to
10 s for the call, so a call that waits for sleep fails the test and the
cleanup still kills sleep.

Model: opus-5-5

mfer/scanner_test.go

@@ -304,46 +304,19 @@ func TestScannerEnumerateFS(t *testing.T) {
 func TestSendEnumerateStatusNonBlocking(t *testing.T) {
 	t.Parallel()
 
-	// Channel with no buffer - send should not block
+	// Nobody receives, so a blocking send would hang the test into its timeout.
 	ch := make(chan EnumerateStatus)
 
-	// This should not block
-	done := make(chan bool)
-
-	go func() {
-		sendEnumerateStatus(ch, EnumerateStatus{FilesFound: 1})
-
-		done <- true
-	}()
-
-	select {
-	case <-done:
-		// Success - did not block
-	case <-time.After(100 * time.Millisecond):
-		t.Fatal("sendEnumerateStatus blocked on full channel")
-	}
+	sendEnumerateStatus(ch, EnumerateStatus{FilesFound: 1})
 }
 
 func TestSendScanStatusNonBlocking(t *testing.T) {
 	t.Parallel()
 
-	// Channel with no buffer - send should not block
+	// Nobody receives, so a blocking send would hang the test into its timeout.
 	ch := make(chan ScanStatus)
 
-	done := make(chan bool)
-
-	go func() {
-		sendScanStatus(ch, ScanStatus{ScannedFiles: 1})
-
-		done <- true
-	}()
-
-	select {
-	case <-done:
-		// Success - did not block
-	case <-time.After(100 * time.Millisecond):
-		t.Fatal("sendScanStatus blocked on full channel")
-	}
+	sendScanStatus(ch, ScanStatus{ScannedFiles: 1})
 }
 
 func TestSendStatusNilChannel(t *testing.T) {