Stage 8 — Smart Pricing Engine: contextual coefficients

Contextual multipliers layered on top of base MarkupRule pricing, applied
per work-order line based on vehicle, client and urgency.

Schema:
- pricing_coefficients (multiplier, conditions JSON, priority, stackable)
- vehicles.vehicle_class (sedan/suv/commercial/hybrid/ev/premium)
- clients.is_vip
- work_orders.urgency (normal/urgent/express)

PricingEngine::quote(Part, Vehicle?, Client?, urgency):
- base = MarkupRule on buy_price (fallback sell_price or buy×1.30)
- context: class (explicit or inferred hybrid/ev from fuel), age, vip, urgency
- stackable coefficients all multiply; non-stackable take only the highest
- returns {base, final, applied[]} breakdown

PricingCoefficient::matches(ctx) — classes/age range/vip/urgency conditions
(empty = always applies).

Filament:
- PricingCoefficientResource with condition builder (classes, age, vip, urgency)
- vehicle_class select, client is_vip toggle, WO urgency select
- "Preț inteligent" action on WO parts shows breakdown + applies sell_price

Tests (6 new):
- base-only without coefficients; age coefficient gating; VIP; express urgency;
  stackable multiply vs non-stackable highest-wins; hybrid inferred from fuel

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

app/Models/Tenant/Vehicle.php

@@ -15,7 +15,7 @@ class Vehicle extends Model
     protected $fillable = [
         'company_id', 'client_id',
         'make', 'model', 'year', 'vin', 'plate',
-        'engine', 'gearbox', 'fuel', 'mileage', 'color', 'notes',
+        'engine', 'gearbox', 'fuel', 'vehicle_class', 'mileage', 'color', 'notes',
     ];
 
     public function client(): BelongsTo