Fix stale cursor line after a sync completes in the foreground

renderStatus() only rewrote the status TextView, so the 'Last sync cursor'
line kept its launch-time value until the next onResume - on a fresh install a
successful sync still displayed 'never'. It now delegates to refreshStatus()
which refreshes both lines.

app/src/main/java/com/bm/andpictures/MainActivity.kt

@@ -218,12 +218,17 @@ class MainActivity : AppCompatActivity() {
         statusText.text = p.lastStatus.ifBlank { getString(R.string.status_idle) }
     }
 
-    /** Repaints the status line from whatever sync is in flight right now. */
+    /**
+     * Repaints the status/cursor lines from whatever sync is in flight right now.
+     * When nothing is running this delegates to [refreshStatus] so the cursor line
+     * also refreshes while the app stays in the foreground (otherwise a completed
+     * sync would leave a stale "Last sync cursor" until the next onResume).
+     */
     private fun renderStatus() {
-        statusText.text = if (oneShotSyncActive || periodicSyncRunning) {
-            "Syncing…"
+        if (oneShotSyncActive || periodicSyncRunning) {
+            statusText.text = "Syncing…"
         } else {
-            Prefs(this).lastStatus.ifBlank { getString(R.string.status_idle) }
+            refreshStatus()
         }
     }