Port Telemetry, Format, RideStatistics; add cross-language parity harness

T03 — telemetry.dart, format.dart, live_telemetry.dart, plus pure domain models
(Trip/Segment/TrackPoint/RideStats) with no persistence dependency, so Drift can
map to them in T08 rather than the domain depending on the database.

T04 — ride_statistics.dart including ElevationAccumulator, ported structurally
faithfully: moving average, reversal hysteresis, gainIncludingPending, and the
finish() reconciliation against lastRaw.

T07 (early, because T04 forced it) — tool/parity/ drives identical fixtures
through the real Kotlin files and the Dart port, then diffs. Result: every value
byte-identical, including noisy_gain=38.959594555022136 to the last digit. The
sole difference is run_avg_speed, where Kotlin's 32-bit Float widens to double
with artefacts Dart's binary64 does not reproduce. Documented, not papered over.

That harness settled a real question. The ported elevation test failed at 50.9m
against Kotlin's 35m bound, which looked like a porting bug. It was not: Kotlin's
and Dart's Random(42) are different streams. On a shared LCG fixture both produce
39.0m -- which would also fail Kotlin's own bound. The native guard passes on seed
luck rather than on a property of the algorithm. The Dart test now uses the shared
LCG, asserts bit-equality with Kotlin, and sets its bound from measured behaviour
(25 seeds spanned 24.7-46.7m).

52 tests passing.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

lib/src/ui/format.dart

@@ -0,0 +1,35 @@
+/// Display formatting shared across screens.
+///
+/// Ported from `com.rippr.ui.Format`.
+///
+/// Timestamps come from the platform location fix, which is UTC epoch millis, so
+/// everything here converts to the device zone. Formatting in UTC would show a 21:00
+/// ride as tomorrow.
+library;
+
+import 'package:intl/intl.dart';
+
+import '../domain/models.dart';
+
+// Built per call rather than cached in a top-level final. The Kotlin original captured
+// Locale.getDefault() once at class-init; doing the same here would freeze the format
+// for the process lifetime and ignore a locale change.
+DateFormat get _dayTime => DateFormat("EEE d MMM '·' HH:mm");
+DateFormat get _fileStamp => DateFormat('yyyy-MM-dd-HHmm');
+
+String formatDateTime(int epochMillis) =>
+    _dayTime.format(DateTime.fromMillisecondsSinceEpoch(epochMillis));
+
+String formatFileTimestamp(int epochMillis) =>
+    _fileStamp.format(DateTime.fromMillisecondsSinceEpoch(epochMillis));
+
+/// A trip's own name, or a date-derived label when it has none.
+String tripLabel(Trip trip) => trip.name ?? formatDateTime(trip.startedAt);
+
+String formatDistance(double meters) => meters < 1000
+    ? '${meters.toInt()} m'
+    : '${(meters / 1000).toStringAsFixed(1)} km';
+
+String formatSpeed(double kmh) => '${kmh.toStringAsFixed(1)} km/h';
+
+String formatElevation(double meters) => '${meters.toInt()} m';