i18n: fix widget heading, translate Select options from model consts, +40 keys

- LowStockTable: rename getHeading → getTableHeading (correct Filament API)
- Global I18n::opts() helper wraps Model::CONST values in __() so
  Select dropdowns show translated status/type/season/etc. labels
- Sed-transform ->options(X::CONST), ->options(array_combine(X::A,X::A)),
  and formatStateUsing(fn($s)=>X::CONST[$s]??$s) → wrap with __()
  (58 options + 10 combines + 7 formatStateUsing across 28 files)
- CalendarBoard: all 7 day names now via __() (was missing 4)
- calendar-board.blade: fix untranslated 'săptămâna curentă', 'capacitate',
  'rata confirmare', 'mediu', 'plin', 'Pod / Zi' / 'Mecanic / Zi'
- +40 RU/EN translations (Client & Auto, Maistru / Mecanic, Programat,
  Sosit, Finalizat, Anulat, Neprezentat, days of week, calendar KPIs)

All 306 tests pass.

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

app/Filament/Tenant/Resources/MessageTemplateResource.php

@@ -52,7 +52,7 @@ class MessageTemplateResource extends Resource
                 ->schema([
                     Forms\Components\TextInput::make('name')->label(__('Nume template'))->required()->maxLength(120),
                     Forms\Components\Select::make('channel')
-                        ->options(MessageTemplate::CHANNELS)
+                        ->options(\App\Support\I18n::opts(MessageTemplate::CHANNELS))
                         ->default('telegram')
                         ->required(),
                     Forms\Components\TextInput::make('subject')->label(__('Subiect (email)'))->maxLength(160)->columnSpanFull(),
@@ -82,7 +82,7 @@ class MessageTemplateResource extends Resource
                 Tables\Columns\IconColumn::make('is_active')->boolean(),
             ])
             ->filters([
-                Tables\Filters\SelectFilter::make('channel')->options(MessageTemplate::CHANNELS),
+                Tables\Filters\SelectFilter::make('channel')->options(\App\Support\I18n::opts(MessageTemplate::CHANNELS)),
             ])
             ->actions([
                 Actions\EditAction::make(),