feat(trips): live mid-trip truck load input with Pusher broadcast

- Migration: add current_load_kg (nullable unsigned int) to trips table
- Trip model: add current_load_kg to fillable + integer cast
- New TruckLoadBroadcast event (ShouldBroadcastNow)
  - Channel: private admin.live
  - Event name: truck.load
  - Payload: trip_id, team_id, truck_id, current_load_kg, capacity_kg, is_full
- DriverTripController::updateLoad()
  - PATCH /api/v1/driver/trips/{trip}/update-load
  - Validates status is in_progress, saves current_load_kg, fires broadcast
- Route: PATCH driver/trips/{trip}/update-load registered
- CollectionTeamResource: truck_is_full uses current_load_kg (live estimate)
  with fallback to total_load_kg (authoritative dumpsite weight)
- TripResource: expose current_load_kg field
- Admin Teams card:
  - data-team-id attribute added to each card for Echo targeting
  - Load bar uses current_load_kg when available
  - Echo listener for truck.load event patches load bar + badge in real-time
  - truck-status-badge class added to Collecting/Truck Full spans

app/Http/Resources/CollectionTeamResource.php

@@ -30,14 +30,12 @@ class CollectionTeamResource extends JsonResource
             'is_full' => $this->is_full,
             'truck_is_full' => $this->whenLoaded('currentTrip', function () {
                 $trip = $this->currentTrip;
-                if (! $trip) {
-                    return false;
-                }
-                $atDumpsite = $trip->status === Trip::STATUS_AT_DUMPSITE;
-                $atCapacity = $this->truck?->capacity_kg > 0
-                    && $trip->total_load_kg >= $this->truck->capacity_kg;
-
-                return $atDumpsite || $atCapacity;
+                if (! $trip) return false;
+                $capacity = $this->truck?->capacity_kg;
+                // Prefer driver's live estimate; fall back to dumpsite-scale total
+                $effectiveLoad = $trip->current_load_kg ?? $trip->total_load_kg ?? 0;
+                return ($capacity && $effectiveLoad >= $capacity)
+                    || $trip->status === 'at_dumpsite';
             }, false),
             'performance_stats' => $this->getPerformanceStats(),
             'current_trip' => TripResource::make($this->whenLoaded('currentTrip')),