collect: fix stale vehicle ref after token re-login; increase update verbosity

After a full re-login (doLogin), the library rebuilds its vehicle list with
new objects. The old vehicle reference in the collect loop was never updated
again, causing data to silently freeze. Re-select the vehicle from wc.vehicles
after every update() call to stay on the current object.

Also: update() now returns and logs its bool result; the record log line shows
which top-level keys changed each cycle (or "none" when the backend returned
identical data).

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

server/we_connect.py

@@ -60,5 +60,11 @@ def select_vehicle(wc: _Session, vin: str | None):
     return vehicles[0], None
 
 
-def update(wc: _Session) -> None:
-    wc.run(wc.connection.update())
+def update(wc: _Session) -> bool:
+    """Run one update cycle. Returns True if the library reported success."""
+    ok = wc.run(wc.connection.update())
+    if not ok:
+        log.warning("connection.update() returned False — data may not have refreshed")
+    else:
+        log.debug("connection.update() succeeded")
+    return bool(ok)