improve WO form: inline client/vehicle create, mechanic filter, category translation, PDF emoji fix

- client_id field: switched to relationship() with createOptionForm so new clients
  can be created inline (name, phone, email); search also matches by phone
- vehicle_id field: added createOptionForm (make, model, plate, year, VIN); newly
  created vehicle is automatically linked to the currently selected client
- master_id field: now shows only active users with role mechanic/master
- WorksRelationManager: labor catalog select marked optional; added createOptionForm
  so new catalog entries can be added without leaving the WO form
- SubcontractJobsRelationManager: category table column now translates value via __()
  and shows explicit label(__('Categorie'))
- PDF work-order: replaced 📞 / ✉ / ⚠ emojis with plain-text equivalents so
  DomPDF/DejaVu Sans renders them correctly instead of showing "????"

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

app/Filament/Tenant/Resources/WorkOrderResource/RelationManagers/SubcontractJobsRelationManager.php

@@ -51,7 +51,9 @@ class SubcontractJobsRelationManager extends RelationManager
             ->columns([
                 Tables\Columns\TextColumn::make('number')->label(__('Nr.')),
                 Tables\Columns\TextColumn::make('subcontractor.name')->label(__('Terț'))->placeholder('—'),
-                Tables\Columns\TextColumn::make('category')->badge()->placeholder('—'),
+                Tables\Columns\TextColumn::make('category')->label(__('Categorie'))
+                    ->formatStateUsing(fn ($s) => $s ? __($s) : '—')
+                    ->badge()->placeholder('—'),
                 Tables\Columns\TextColumn::make('cost')->money('MDL')->alignRight(),
                 Tables\Columns\TextColumn::make('client_price')->label(__('Preț client'))->money('MDL')->alignRight(),
                 Tables\Columns\TextColumn::make('margin')