fix: store opened_at and closed_at as DATETIME (not DATE)

DATE columns lose time information, causing timeline to show 00:00 for
car reception and WO closure. Migrated both columns to DATETIME and
updated: model casts (date → datetime), form pickers (DatePicker →
DateTimePicker with seconds:false), default to now() instead of today(),
and cleaned up defensive Carbon::parse() in getTimeline().

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

app/Filament/Tenant/Resources/WorkOrderResource.php

@@ -80,7 +80,7 @@ class WorkOrderResource extends Resource
                 ->columns(4)
                 ->schema([
                     Forms\Components\TextInput::make('number')->label(__('Nr.'))->disabled()->dehydrated(false)->placeholder('auto'),
-                    Forms\Components\DatePicker::make('opened_at')->label(__('Deschis'))->default(today())->required(),
+                    Forms\Components\DateTimePicker::make('opened_at')->label(__('Deschis'))->default(now())->seconds(false)->required(),
                     Forms\Components\Select::make('status')->options(\App\Support\I18n::opts(WorkOrder::STATUSES))->default('new')->required(),
                     Forms\Components\Select::make('urgency')->label(__('Urgență'))
                         ->options(\App\Support\I18n::opts(\App\Models\Tenant\PricingCoefficient::URGENCY))->default('normal')->required(),
@@ -192,7 +192,7 @@ class WorkOrderResource extends Resource
                             'style' => 'font-weight:600;color:' . ($record && $record->paidAmount() >= (float)$record->total ? '#16a34a' : '#dc2626'),
                         ]),
                     Forms\Components\Toggle::make('approved')->label(__('Aprobat de client')),
-                    Forms\Components\DatePicker::make('closed_at')->label(__('Închis')),
+                    Forms\Components\DateTimePicker::make('closed_at')->label(__('Închis'))->seconds(false),
                 ]),
         ]);
     }