Fix European trip return heuristic for weekend location tracking

Adjust European short trip heuristic from >3 days to >1 day to correctly
detect when user has returned home from European trips. This fixes the
April 29-30, 2023 case where the location incorrectly showed "Sankt Georg, Hamburg"
instead of "Bristol" when the user was free (no events scheduled) after
the foss-north trip ended on April 27.

The previous logic required more than 3 days to pass before assuming
return home from European countries, but for short European trips by
rail/ferry, users typically return within 1-2 days.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

node_modules/@humanwhocodes/object-schema/src/merge-strategy.js

@@ -0,0 +1,53 @@
+/**
+ * @filedescription Merge Strategy
+ */
+
+"use strict";
+
+//-----------------------------------------------------------------------------
+// Class
+//-----------------------------------------------------------------------------
+
+/**
+ * Container class for several different merge strategies.
+ */
+class MergeStrategy {
+
+    /**
+     * Merges two keys by overwriting the first with the second.
+     * @param {*} value1 The value from the first object key. 
+     * @param {*} value2 The value from the second object key.
+     * @returns {*} The second value.
+     */
+    static overwrite(value1, value2) {
+        return value2;
+    }
+
+    /**
+     * Merges two keys by replacing the first with the second only if the
+     * second is defined.
+     * @param {*} value1 The value from the first object key. 
+     * @param {*} value2 The value from the second object key.
+     * @returns {*} The second value if it is defined.
+     */
+    static replace(value1, value2) {
+        if (typeof value2 !== "undefined") {
+            return value2;
+        }
+
+        return value1;
+    }
+
+    /**
+     * Merges two properties by assigning properties from the second to the first.
+     * @param {*} value1 The value from the first object key.
+     * @param {*} value2 The value from the second object key.
+     * @returns {*} A new object containing properties from both value1 and
+     *      value2.
+     */
+    static assign(value1, value2) {
+        return Object.assign({}, value1, value2);
+    }
+}
+
+exports.MergeStrategy = MergeStrategy;