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/@webassemblyjs/utf8/test/index.js

@@ -0,0 +1,13 @@
+const { assert } = require("chai");
+
+const { decode, encode } = require("../lib");
+
+describe("UTF8", () => {
+  it("should f-1(f(x)) = x", () => {
+    assert.equal(decode(encode("foo")), "foo");
+    assert.equal(decode(encode("éé")), "éé");
+
+    // TODO(sven): utf8 encoder fails here
+    // assert.equal(decode(encode("🤣见見")), "🤣见見");
+  });
+});