feat: Garmin gear sync — registry + per-activity gear on sync and backfill

- garmin_sync_iter: sync gear registry from Garmin on every sync run and
  resolve gear for each newly imported activity via get_activity_gear()
- POST /api/garmin/import-gear: one-time backfill that matches Garmin gear
  activities to existing local activities by UTC timestamp (±60 s)

bincio/extract/garmin_sync.py

@@ -22,9 +22,9 @@ from __future__ import annotations
 import io
 import json
 import zipfile
-from datetime import datetime, timedelta, timezone
+from collections.abc import Generator
+from datetime import UTC, datetime, timedelta
 from pathlib import Path
-from typing import Generator
 
 _SYNC_FILE = "garmin_sync.json"
 
@@ -73,9 +73,13 @@ def garmin_sync_iter(
         data_dir:  Root data directory (used for encryption key lookup).
         user_dir:  Per-user directory (contains activities/, garmin_creds.json, etc.).
     """
+    import uuid as _uuid
+
     from bincio.extract.garmin_api import GarminError, get_client
     from bincio.extract.ingest import ingest_parsed
     from bincio.extract.parsers.fit import FitParser
+    from bincio.serve.routers.gear import _load as _gear_load
+    from bincio.serve.routers.gear import _save as _gear_save
 
     # ── Login ──────────────────────────────────────────────────────────────────
     try:
@@ -86,6 +90,41 @@ def garmin_sync_iter(
 
     yield {"type": "fetching"}
 
+    # ── Sync gear registry ─────────────────────────────────────────────────────
+    _garmin_uuid_to_name: dict[str, str] = {}
+    try:
+        prof = client.connectapi("/userprofile-service/socialProfile")
+        profile_id = prof.get("profileId") if isinstance(prof, dict) else None
+        if profile_id:
+            garmin_gear = client.get_gear(profile_id)
+            if isinstance(garmin_gear, list):
+                registry = _gear_load(user_dir)
+                known = {g.get("garmin_id") for g in registry if g.get("garmin_id")}
+                for g in garmin_gear:
+                    guuid = g.get("uuid") or ""
+                    name = (g.get("customMakeModel") or g.get("displayName") or
+                            f"{g.get('gearMakeName','')} {g.get('gearModelName','')}".strip())
+                    if not name or not guuid:
+                        continue
+                    _garmin_uuid_to_name[guuid] = name
+                    if guuid not in known:
+                        gear_type = g.get("gearTypeName", "").lower()
+                        if gear_type not in ("bike", "shoes", "skis"):
+                            gear_type = "other"
+                        retired = g.get("gearStatusName") == "retired"
+                        registry.append({"id": str(_uuid.uuid4()), "name": name,
+                                         "type": gear_type, "retired": retired,
+                                         "garmin_id": guuid})
+                        known.add(guuid)
+                    else:
+                        # Update name in case it changed
+                        for item in registry:
+                            if item.get("garmin_id") == guuid:
+                                item["name"] = name
+                _gear_save(user_dir, registry)
+    except Exception:
+        pass  # gear sync is best-effort; don't abort activity sync
+
     # ── Determine date range ───────────────────────────────────────────────────
     state = _load_sync_state(user_dir)
     last = state.get("last_sync_at")
@@ -144,6 +183,16 @@ def garmin_sync_iter(
             except Exception as exc:
                 raise RuntimeError(f"FIT parse error: {exc}") from exc
 
+            # Resolve gear for this activity
+            if garmin_id and _garmin_uuid_to_name:
+                try:
+                    act_gear = client.get_activity_gear(garmin_id)
+                    if isinstance(act_gear, list) and act_gear:
+                        guuid = act_gear[0].get("uuid") or ""
+                        parsed.gear = _garmin_uuid_to_name.get(guuid) or None
+                except Exception:
+                    pass
+
             # Ingest — raises FileExistsError if already present (dedup)
             ingest_parsed(parsed, user_dir)
             imported += 1
@@ -173,7 +222,7 @@ def garmin_sync_iter(
             }
 
     # ── Persist sync state ─────────────────────────────────────────────────────
-    state["last_sync_at"] = datetime.now(timezone.utc).strftime("%Y-%m-%d")
+    state["last_sync_at"] = datetime.now(UTC).strftime("%Y-%m-%d")
     state["total_imported"] = state.get("total_imported", 0) + imported
     _save_sync_state(user_dir, state)