feat(F-138): completed feature

project/src/modules/pricing/application/pricing-service.ts

@@ -42,6 +42,10 @@ export class PricingService implements PricingServicePort {
     ensureNonNegativeInteger(input.netUnitAmountCents, 'Price must be a non-negative integer');
     return this.repository.setVariantPrice(input);
   }
+
+  async seedVariantPrice(variantId: string): Promise<void> {
+    await this.repository.seedVariantPrice(variantId);
+  }
 }
 
 function ensurePositiveInteger(value: number, message: string): void {

project/src/modules/pricing/domain/ports.ts

@@ -9,9 +9,16 @@ export interface PricingService {
   calculate(input: PriceCalculationCommand): Promise<PriceCalculation>;
   getVariantPrice(variantId: string): Promise<VariantPrice | undefined>;
   setVariantPrice(input: SetVariantPriceCommand): Promise<VariantPrice>;
+  /**
+   * Seeds a neutral default price row for a freshly created variant so that
+   * GET /pricing/variants/:id never 404s right after creation (F-138). Idempotent:
+   * no-op when a row already exists for the given variant_id.
+   */
+  seedVariantPrice(variantId: string): Promise<void>;
 }
 
 export interface PricingRepository {
   findByVariantId(variantId: string): Promise<VariantPrice | undefined>;
   setVariantPrice(input: SetVariantPriceCommand): Promise<VariantPrice>;
+  seedVariantPrice(variantId: string): Promise<void>;
 }

project/src/modules/pricing/infrastructure/pg-pricing-repository.ts

@@ -25,6 +25,15 @@ export class PgPricingRepository implements PricingRepository {
     return row ? toVariantPrice(row) : undefined;
   }
 
+  async seedVariantPrice(variantId: string): Promise<void> {
+    await this.pool.query(
+      `INSERT INTO pricing_variant_prices (variant_id, net_unit_amount_cents, offer_cents, cost_cents, vat_rate)
+       VALUES ($1, 0, NULL, NULL, 'general')
+       ON CONFLICT (variant_id) DO NOTHING`,
+      [variantId],
+    );
+  }
+
   async setVariantPrice(input: SetVariantPriceCommand): Promise<VariantPrice> {
     const client = await this.pool.connect();
     try {

project/src/modules/pricing/tests/pricing-service.test.ts

@@ -19,6 +19,7 @@ function repository(overrides: Partial<PricingRepository> = {}): PricingReposito
   return {
     findByVariantId: async () => PRICE,
     setVariantPrice: async (_input: SetVariantPriceCommand) => PRICE,
+    seedVariantPrice: async () => undefined,
     ...overrides,
   };
 }