Drop "Details:" label from the mission stats pill to save footer space

The icons (flag/ruler/clock) already convey what each value means, so
the label was redundant. Gave the pill a stable Key since tests relied
on the now-removed text to find and tap it.

app/lib/ui/widgets/bottom_stats_bar.dart

@@ -249,6 +249,11 @@ class BottomStatsBar extends ConsumerWidget {
         : _fmtDuration(totalDurationSec);
 
     return GestureDetector(
+      // Testhaken (siehe widget_test.dart): seit dem Entfernen des
+      // "Details:"-Labels (Nutzerwunsch: Platz sparen in Plan- und
+      // Fly-Modus) gibt es keinen eindeutigen Text mehr, um die Pille in
+      // Tests anzutippen.
+      key: const Key('detailsPill'),
       onTap: onTap,
       child: Container(
         height: _footerElementHeight,
@@ -260,15 +265,6 @@ class BottomStatsBar extends ConsumerWidget {
         child: Row(
           mainAxisSize: MainAxisSize.min,
           children: [
-            const Text(
-              'Details:',
-              style: TextStyle(
-                color: Colors.white70,
-                fontWeight: _footerFontWeight,
-                fontSize: _footerFontSize,
-              ),
-            ),
-            const SizedBox(width: 10),
             const Icon(Icons.flag, size: _footerIconSize, color: Colors.white),
             const SizedBox(width: 4),
             Text(waypointText,