Phase 1: foundation modules

Central Config with all tunables (retention, GPS timeout, colors,
event type keys, menu item metadata). Event / EventStore handle
persistence via Application.Storage with 7-day pruning. Logger
mirrors the same retention. LayoutMetrics and Haversine provide
resolution-independent geometry helpers. German UI strings and
placeholder menu icons landed alongside so the build stays green.

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

source/Logger.mc

@@ -0,0 +1,49 @@
+import Toybox.Application;
+import Toybox.Lang;
+import Toybox.Time;
+
+// Lightweight crash / diagnostic logger. Entries live in
+// Application.Storage and are pruned with the same retention window
+// as events so the watch storage never fills up.
+module Logger {
+
+    const KEY = "logs";
+    const MAX_ENTRIES = 50;
+
+    function log(msg as String) as Void {
+        var raw = Application.Storage.getValue(KEY);
+        var arr = (raw instanceof Array) ? raw : [];
+        arr.add({
+            "ts"  => Time.now().value(),
+            "msg" => msg
+        });
+        if (arr.size() > MAX_ENTRIES) {
+            arr = arr.slice(arr.size() - MAX_ENTRIES, arr.size());
+        }
+        Application.Storage.setValue(KEY, arr);
+    }
+
+    function getAll() as Array<Dictionary> {
+        var raw = Application.Storage.getValue(KEY);
+        return (raw instanceof Array) ? raw : [];
+    }
+
+    function pruneOld() as Void {
+        var raw = Application.Storage.getValue(KEY);
+        if (!(raw instanceof Array) || raw.size() == 0) {
+            return;
+        }
+        var cutoff = Time.now().value() - Config.RETENTION_SEC;
+        var kept = [];
+        for (var i = 0; i < raw.size(); i++) {
+            var d = raw[i] as Dictionary;
+            var ts = d["ts"];
+            if (ts != null && (ts as Number) >= cutoff) {
+                kept.add(d);
+            }
+        }
+        if (kept.size() != raw.size()) {
+            Application.Storage.setValue(KEY, kept);
+        }
+    }
+}