Fix sleep score parsing, dashboard body battery, segment direction

- Garmin sync: read sleepScores from dailySleepDTO (Garmin nests it there),
  so sleep score is actually stored instead of always null
- Dashboard: pass YYYY-MM-DD to the intraday endpoint (was a full ISO
  timestamp), so the body-battery tile populates
- Segment matching: follow the segment in its created direction with a
  path-length sanity check, so out-and-back routes no longer match an early
  start pass to a late finish (the >1h bogus segment times)

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

backend/app/services/garmin_connect_sync.py

@@ -555,8 +555,10 @@ def _parse_day(stats, sleep_data, hrv_data) -> dict:
         if spo2 and 50 < float(spo2) <= 100:
             row["spo2_avg"] = float(spo2)
 
-        # Sleep score — structure varies across firmware
-        scores = sleep_data.get("sleepScores") or sleep_data.get("sleepScore")
+        # Sleep score — Garmin nests it under dailySleepDTO.sleepScores on most
+        # firmware, but some return it at the top level; check both.
+        scores = (dto.get("sleepScores") or sleep_data.get("sleepScores")
+                  or dto.get("sleepScore") or sleep_data.get("sleepScore"))
         if isinstance(scores, dict):
             overall = scores.get("overall") or scores.get("qualityScore")
             if isinstance(overall, dict):