feat: add ownership-costs feature capsule (refs #15)

- Create ownership_costs table for recurring vehicle costs
- Add backend feature capsule with types, repository, service, routes
- Update TCO calculation to use ownership_costs (with fallback to legacy vehicle fields)
- Add taxCosts and otherCosts to TCO response
- Create frontend ownership-costs feature with form, list, API, hooks
- Update TCODisplay to show all cost types

This implements a more flexible approach to tracking recurring ownership costs
(insurance, registration, tax, other) with explicit date ranges and optional
document association.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

backend/src/features/vehicles/domain/vehicles.service.ts

@@ -28,6 +28,7 @@ import { NHTSAClient, NHTSADecodeResponse, DecodedVehicleData, MatchedField } fr
 import { canAddVehicle, getVehicleLimitConfig } from '../../../core/config/feature-tiers';
 import { UserProfileRepository } from '../../user-profile/data/user-profile.repository';
 import { SubscriptionTier } from '../../user-profile/domain/user-profile.types';
+import { OwnershipCostsService } from '../../ownership-costs';
 import { FuelLogsService } from '../../fuel-logs/domain/fuel-logs.service';
 import { FuelLogsRepository } from '../../fuel-logs/data/fuel-logs.repository';
 import { MaintenanceService } from '../../maintenance/domain/maintenance.service';
@@ -430,20 +431,35 @@ export class VehiclesService {
     // Get fixed costs from vehicle record
     const purchasePrice = vehicle.purchasePrice || 0;
 
-    // Normalize recurring costs based on purchase date
-    const insuranceCosts = this.normalizeRecurringCost(
-      vehicle.insuranceCost,
-      vehicle.insuranceInterval,
-      vehicle.purchaseDate
-    );
-    const registrationCosts = this.normalizeRecurringCost(
-      vehicle.registrationCost,
-      vehicle.registrationInterval,
-      vehicle.purchaseDate
-    );
+    // Get recurring ownership costs from ownership-costs service
+    const ownershipCostsService = new OwnershipCostsService(this.pool);
+    let insuranceCosts = 0;
+    let registrationCosts = 0;
+    let taxCosts = 0;
+    let otherCosts = 0;
+    try {
+      const ownershipStats = await ownershipCostsService.getVehicleCostStats(id, userId);
+      insuranceCosts = ownershipStats.insuranceCosts || 0;
+      registrationCosts = ownershipStats.registrationCosts || 0;
+      taxCosts = ownershipStats.taxCosts || 0;
+      otherCosts = ownershipStats.otherCosts || 0;
+    } catch {
+      // Vehicle may have no ownership cost records
+      // Fall back to legacy vehicle fields if they exist
+      insuranceCosts = this.normalizeRecurringCost(
+        vehicle.insuranceCost,
+        vehicle.insuranceInterval,
+        vehicle.purchaseDate
+      );
+      registrationCosts = this.normalizeRecurringCost(
+        vehicle.registrationCost,
+        vehicle.registrationInterval,
+        vehicle.purchaseDate
+      );
+    }
 
-    // Calculate lifetime total
-    const lifetimeTotal = purchasePrice + insuranceCosts + registrationCosts + fuelCosts + maintenanceCosts;
+    // Calculate lifetime total (includes all ownership costs: insurance, registration, tax, other)
+    const lifetimeTotal = purchasePrice + insuranceCosts + registrationCosts + taxCosts + otherCosts + fuelCosts + maintenanceCosts;
 
     // Calculate cost per distance
     const odometerReading = vehicle.odometerReading || 0;
@@ -454,6 +470,8 @@ export class VehiclesService {
       purchasePrice,
       insuranceCosts,
       registrationCosts,
+      taxCosts,
+      otherCosts,
       fuelCosts,
       maintenanceCosts,
       lifetimeTotal,

backend/src/features/vehicles/domain/vehicles.types.ts

@@ -201,6 +201,8 @@ export interface TCOResponse {
   purchasePrice: number;
   insuranceCosts: number;
   registrationCosts: number;
+  taxCosts: number;
+  otherCosts: number;
   fuelCosts: number;
   maintenanceCosts: number;
   lifetimeTotal: number;