Add a persisted test suite

`bundle exec rake test` (minitest, a default gem but pinned in
Gemfile for reproducibility) now covers what ad-hoc scripts kept
re-verifying by hand during development: Gpx/Fit/TrackStats parsing,
GpxStore/LiveTrackStore file/TTL logic, LiveTrackClient's payload
parsing, and app.rb's routes end to end via Rack::MockRequest.

MAPTOOL_DATA_DIR (new, app.rb) lets the suite point GPX_STORE/
LIVETRACK_STORE at a throwaway directory instead of real data/ —
without it every run would leave uploaded test files behind. Each
lib file's old `if __FILE__ == $0` self-check is now redundant with
real tests covering the same ground, so removed rather than kept as
a second copy of the same assertions. Wired into ci.yml so it isn't
just a local convenience.

test/test_livetrack_store.rb

@@ -0,0 +1,63 @@
+require_relative "test_helper"
+require "maptool/livetrack_store"
+
+class LiveTrackStoreTest < Minitest::Test
+  def setup
+    @store = Maptool::LiveTrackStore.new(File.join(Dir.mktmpdir, "livetrack.json"))
+  end
+
+  def test_starts_empty
+    assert_empty @store.list
+  end
+
+  def test_add_and_find
+    @store.add("abc123", "tok-abc")
+    @store.add("def456", "tok-def")
+
+    assert_equal 2, @store.list.size
+    assert_equal "def456", @store.list.first["id"], "newest received first"
+    assert_equal "tok-abc", @store.find("abc123")["token"]
+    assert_nil @store.find("nope")
+  end
+
+  def test_re_adding_moves_to_front_without_duplicating
+    @store.add("abc123", "tok-abc")
+    @store.add("def456", "tok-def")
+    @store.add("abc123", "tok-abc-2")
+
+    assert_equal %w[abc123 def456], @store.list.map { |s| s["id"] }
+    assert_equal "tok-abc-2", @store.find("abc123")["token"], "token updated on re-add"
+  end
+
+  def test_summary_carries_over_across_re_add
+    @store.add("abc123", "tok-abc")
+    @store.set_summary("abc123", { "session_name" => "Test Ride" })
+    @store.add("abc123", "tok-abc-2")
+
+    assert_equal({ "session_name" => "Test Ride" }, @store.find("abc123")["summary"])
+  end
+
+  def test_unsummarized_sessions_are_pruned_after_the_ttl_but_summarized_ones_are_kept
+    @store.add("old_no_summary", "tok1")
+    @store.add("old_with_summary", "tok2")
+    @store.set_summary("old_with_summary", { "session_name" => "Kept" })
+
+    path = @store.instance_variable_get(:@path)
+    raw = JSON.parse(File.read(path))
+    raw.each { |s| s["received_at"] = (Time.now.utc - 1000 * 60 * 60).iso8601 }
+    File.write(path, JSON.generate(raw))
+
+    reloaded = Maptool::LiveTrackStore.new(path)
+    ids = reloaded.list.map { |s| s["id"] }
+    refute_includes ids, "old_no_summary"
+    assert_includes ids, "old_with_summary"
+  end
+
+  def test_data_survives_reload_from_disk
+    @store.add("abc123", "tok-abc")
+    path = @store.instance_variable_get(:@path)
+
+    reloaded = Maptool::LiveTrackStore.new(path)
+    assert_equal 1, reloaded.list.size
+  end
+end