Phase 3: event creation flow (GPS + success / error)

GpsService runs a single-shot position request with a hard timeout
and early-exit when Config.GPS_TARGET_ACCURACY_M is reached.
LoadingView renders a circular progress bar around the edge plus the
"Standort wird bestimmt" prompt; on callback it persists a new Event
via EventStore.add and transitions to SuccessView (green checkmark,
short vibration, auto-close) or ErrorView (red alert, 3× vibration,
German message, longer hold). TextUtils extracts the shared
multi-line centered text rendering so MenuView, LoadingView and
ErrorView all render wrapped German text consistently. Positioning
permission added to manifest.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

source/GpsService.mc

@@ -0,0 +1,60 @@
+import Toybox.Lang;
+import Toybox.Position;
+import Toybox.Timer;
+
+// Single-shot GPS acquisition with a hard timeout. Caller supplies
+// a callback that fires exactly once with either a position fix or
+// null (if nothing usable was received before the timeout). Accuracy
+// shortcut: if the fix already hits Config.GPS_TARGET_ACCURACY_M we
+// stop waiting even if the timeout hasn't expired.
+class GpsService {
+
+    private var _callback as Method(result as Dictionary or Null) as Void;
+    private var _timer as Timer.Timer;
+    private var _finished as Boolean = false;
+    private var _bestFix as Dictionary or Null = null;
+
+    function initialize(callback as Method(result as Dictionary or Null) as Void) {
+        _callback = callback;
+        _timer = new Timer.Timer();
+    }
+
+    function start() as Void {
+        Position.enableLocationEvents(
+            Position.LOCATION_CONTINUOUS,
+            method(:_onPosition)
+        );
+        _timer.start(method(:_onTimeout), Config.GPS_TIMEOUT_MS, false);
+    }
+
+    function _onPosition(info as Position.Info) as Void {
+        if (_finished) { return; }
+        if (info == null || info.position == null) { return; }
+
+        var degrees = info.position.toDegrees();
+        var acc = (info.accuracy != null) ? info.accuracy.toFloat() : null;
+
+        _bestFix = {
+            "lat" => degrees[0].toFloat(),
+            "lon" => degrees[1].toFloat(),
+            "acc" => acc
+        };
+
+        // Good enough → stop early.
+        if (acc != null && acc <= Config.GPS_TARGET_ACCURACY_M) {
+            _finish(_bestFix);
+        }
+    }
+
+    function _onTimeout() as Void {
+        _finish(_bestFix);
+    }
+
+    function _finish(result as Dictionary or Null) as Void {
+        if (_finished) { return; }
+        _finished = true;
+        _timer.stop();
+        Position.enableLocationEvents(Position.LOCATION_DISABLE, method(:_onPosition));
+        _callback.invoke(result);
+    }
+}