refactor: simplify pricing tables to USD-only

- Remove KRW pricing calculations from all pricing tables
- Simplify pricing table to store only wholesale USD prices
- Simplify anvil_pricing to store only retail USD prices
- Remove KRW environment variables (KRW_EXCHANGE_RATE, KRW_MARGIN_RATE)
- Remove KRW functions from constants.ts
- Update GPU/G8/VPU pricing repositories to match
- Add Anvil tables and repositories for branded product support

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

src/repositories/anvil-transfer-pricing.ts

@@ -0,0 +1,91 @@
+/**
+ * Anvil Transfer Pricing Repository
+ * Handles CRUD operations for data transfer pricing per region (USD only)
+ */
+
+import { BaseRepository } from './base';
+import { AnvilTransferPricing, AnvilTransferPricingInput, RepositoryError, ErrorCodes } from '../types';
+import { createLogger } from '../utils/logger';
+
+export class AnvilTransferPricingRepository extends BaseRepository<AnvilTransferPricing> {
+  protected tableName = 'anvil_transfer_pricing';
+  protected logger = createLogger('[AnvilTransferPricingRepository]');
+  protected allowedColumns = [
+    'anvil_region_id',
+    'price_per_gb',
+  ];
+
+  constructor(db: D1Database) {
+    super(db);
+  }
+
+  /**
+   * Find transfer pricing for a specific region
+   */
+  async findByRegion(anvilRegionId: number): Promise<AnvilTransferPricing | null> {
+    try {
+      const result = await this.db
+        .prepare('SELECT * FROM anvil_transfer_pricing WHERE anvil_region_id = ?')
+        .bind(anvilRegionId)
+        .first<AnvilTransferPricing>();
+
+      return result || null;
+    } catch (error) {
+      this.logger.error('findByRegion failed', {
+        anvilRegionId,
+        error: error instanceof Error ? error.message : 'Unknown error'
+      });
+      throw new RepositoryError(
+        `Failed to find transfer pricing for Anvil region: ${anvilRegionId}`,
+        ErrorCodes.DATABASE_ERROR,
+        error
+      );
+    }
+  }
+
+  /**
+   * Bulk upsert transfer pricing records
+   * Uses batch operations for efficiency
+   */
+  async upsertMany(pricing: AnvilTransferPricingInput[]): Promise<number> {
+    if (pricing.length === 0) {
+      return 0;
+    }
+
+    try {
+      const statements = pricing.map((price) => {
+        return this.db.prepare(
+          `INSERT INTO anvil_transfer_pricing (
+            anvil_region_id, price_per_gb
+          ) VALUES (?, ?)
+          ON CONFLICT(anvil_region_id)
+          DO UPDATE SET
+            price_per_gb = excluded.price_per_gb`
+        ).bind(
+          price.anvil_region_id,
+          price.price_per_gb
+        );
+      });
+
+      const results = await this.executeBatch(statements);
+
+      const successCount = results.reduce(
+        (sum, result) => sum + (result.meta.changes ?? 0),
+        0
+      );
+
+      this.logger.info('Upserted Anvil transfer pricing records', { count: successCount });
+      return successCount;
+    } catch (error) {
+      this.logger.error('upsertMany failed', {
+        count: pricing.length,
+        error: error instanceof Error ? error.message : 'Unknown error'
+      });
+      throw new RepositoryError(
+        'Failed to upsert Anvil transfer pricing records',
+        ErrorCodes.TRANSACTION_FAILED,
+        error
+      );
+    }
+  }
+}