Cut Garmin sync API volume; dashboard/health/records/UI improvements

Garmin Connect sync:
- Incremental syncs now re-fetch only a 1-day buffer (yesterday + today)
  instead of the full lookback window every run. Full lookback applies on
  the first sync only. Cuts steady-state API calls ~10x.
- Beat interval is now configurable via GARMIN_SYNC_INTERVAL_MINUTES and
  surfaced to the UI; the sync toggle is relabelled to the real cadence.

Frontend:
- Collapsible sidebar; clearer logged-in user + role display.
- Unified Body Battery colouring between dashboard and health (shared util).
- Sleep score trend chart on health page.
- Segments + medals on the dashboard's most-recent activity.
- Segments tab on the Records page.

Repo hygiene: add .gitignore, untrack committed __pycache__/*.pyc.

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

backend/app/services/garmin_connect_sync.py

@@ -17,6 +17,13 @@ from typing import Optional, Tuple
 
 logger = logging.getLogger(__name__)
 
+# On incremental syncs (last_sync_at is set) only re-fetch the last day or two
+# rather than the full configured lookback window. A 1-day buffer means the
+# window is "yesterday + today", which catches late-arriving / revised data
+# (sleep finalised next morning, body battery, manual weight, HRV status, the
+# midnight boundary) without re-pulling the same N days on every scheduled run.
+INCREMENTAL_BUFFER_DAYS = 1
+
 
 # ── Password encryption ─────────────────────────────────────────────────────
 
@@ -78,9 +85,12 @@ def sync_activities(garmin, user_id: int, since: Optional[datetime],
     List activities from Garmin Connect, skip any already in the DB, download
     FIT ZIPs for new ones, and queue them for processing.
 
-    lookback_days controls the start date on every sync:
-      -1  → full history back to 2010 on first sync, then incremental (since-1d)
-      N   → incremental (since-1d) when since is set; else last N days on first sync
+    lookback_days only sets the window on the FIRST sync (since is None):
+      -1  → full history back to 2010
+      N   → last N days
+    Every subsequent (incremental) sync re-fetches only the last
+    INCREMENTAL_BUFFER_DAYS days, regardless of lookback_days, to avoid
+    re-pulling the whole window on every scheduled run.
     Returns the number of new activities queued.
     """
     import time
@@ -88,15 +98,11 @@ def sync_activities(garmin, user_id: int, since: Optional[datetime],
     from app.models.user import Activity
     from sqlalchemy import select, func
 
-    if lookback_days == -1:
-        # All-time: full pull on first sync, incremental thereafter
-        start_date = (since - timedelta(days=1)).date() if since else date(2010, 1, 1)
-    elif since:
-        # Use whichever is earlier: one day before last sync OR the configured lookback
-        # window. This ensures increasing lookback_days actually fetches older data.
-        incremental = (since - timedelta(days=1)).date()
-        lookback    = date.today() - timedelta(days=max(lookback_days, 1))
-        start_date  = min(incremental, lookback)
+    if since:
+        # Incremental: just the recent buffer (cheap, dedup skips already-imported)
+        start_date = (since - timedelta(days=INCREMENTAL_BUFFER_DAYS)).date()
+    elif lookback_days == -1:
+        start_date = date(2010, 1, 1)
     else:
         start_date = date.today() - timedelta(days=max(lookback_days, 1))
     end_date = date.today()
@@ -195,21 +201,20 @@ def sync_wellness(garmin, user_id: int, since: Optional[datetime], db,
     Fetch daily stats / sleep / HRV from the Garmin Connect JSON API for each
     day in the window and upsert into health_metrics.
 
-    lookback_days controls the window on every sync:
-      -1 → full history back to 2010 on first sync, then incremental (since-1d)
-      N  → incremental (since-1d) when since is set; else last N days on first sync
+    lookback_days only sets the window on the FIRST sync (since is None):
+      -1 → full history back to 2010
+      N  → last N days
+    Every subsequent (incremental) sync re-fetches only the last
+    INCREMENTAL_BUFFER_DAYS days so late-finalised data (sleep, body battery,
+    weight) is corrected without re-pulling the whole window each run.
     Returns the number of days upserted.
     """
     from sqlalchemy import text
 
-    if lookback_days == -1:
-        start_date = (since - timedelta(days=1)).date() if since else date(2010, 1, 1)
-    elif since:
-        # Use whichever is earlier: one day before last sync OR the configured lookback
-        # window. This ensures increasing lookback_days actually fetches older data.
-        incremental = (since - timedelta(days=1)).date()
-        lookback    = date.today() - timedelta(days=max(lookback_days, 1))
-        start_date  = min(incremental, lookback)
+    if since:
+        start_date = (since - timedelta(days=INCREMENTAL_BUFFER_DAYS)).date()
+    elif lookback_days == -1:
+        start_date = date(2010, 1, 1)
     else:
         start_date = date.today() - timedelta(days=max(lookback_days, 1))
     days = (date.today() - start_date).days + 1