feat(i18n): wrap 1103 hardcoded UI strings across Filament with __()

- Convert static $modelLabel/$pluralModelLabel/$title to getter methods
- Wrap ->label()/->placeholder()/->helperText()/->description()/->title()/->body() args
- Wrap Section::make()/Fieldset::make()/Notification::make()->title() args
- Fix RelationManagers::getTitle() signature to match parent (Model, string)
- Fix Pages::getTitle() to instance method (BasePage::getTitle is non-static)
- Extend lang/ru.json + lang/en.json with 700+ common terms; identity fallback for the rest
- Remove duplicate getters in 5 resources that had manual getModelLabel already

All 306 tests pass. Missing translations fall back to the RO key so the UI never breaks.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

app/Filament/Tenant/Widgets/StatsOverview.php

@@ -22,22 +22,22 @@ class StatsOverview extends BaseWidget
 
         return [
             Stat::make('Clienți', Client::count())
-                ->description('Total în baza de date')
+                ->description(__('Total în baza de date'))
                 ->icon('heroicon-o-users')
                 ->color('primary'),
 
             Stat::make('Mașini', Vehicle::count())
-                ->description('Total înregistrate')
+                ->description(__('Total înregistrate'))
                 ->icon('heroicon-o-truck')
                 ->color('info'),
 
             Stat::make('Cereri noi', $newLeads)
-                ->description('De procesat')
+                ->description(__('De procesat'))
                 ->icon('heroicon-o-inbox-arrow-down')
                 ->color($newLeads > 0 ? 'warning' : 'success'),
 
             Stat::make('Deal-uri active', $openDeals)
-                ->description('În pipeline')
+                ->description(__('În pipeline'))
                 ->icon('heroicon-o-funnel')
                 ->color('primary'),