feat: Implement supplier export functionality with workbook generation

- Add `writeSupplierWorkbook` function to create Excel workbooks for supplier analysis results.
- Introduce `SupplierExportSummary` type for summarizing export data.
- Create tests for `writeSupplierWorkbook` to ensure correct sheet creation and data population.
- Implement supplier scoring logic in `supplier-scoring.ts` to evaluate product profitability and demand.
- Add tests for supplier scoring to validate scoring logic and verdict determination.
- Enhance UPC file analysis to integrate supplier scoring and export results to Excel.
- Update database writing logic to accommodate new supplier analysis results.
- Refactor types to include supplier-specific data structures and scoring metrics.
- Ensure proper cleanup of temporary files after tests.

src/database.ts

@@ -1,10 +1,16 @@
 import { Database } from "bun:sqlite";
+import { dirname } from "node:path";
+import { mkdirSync } from "node:fs";
 export { Database } from "bun:sqlite";
 
 let db: Database | null = null;
 
 export function getDb(dbPath: string): Database {
   if (!db) {
+    const dbDir = dirname(dbPath);
+    if (dbDir && dbDir !== ".") {
+      mkdirSync(dbDir, { recursive: true });
+    }
     db = new Database(dbPath);
     db.run("PRAGMA journal_mode = WAL;"); // Enable WAL mode for better performance
     db.run("PRAGMA foreign_keys = ON;"); // Enforce foreign key constraints
@@ -183,6 +189,15 @@ function ensureResultsTableColumns(database: Database): void {
     { name: "lead_date", type: "TEXT" },
     { name: "amazon_is_seller", type: "INTEGER" },
     { name: "amazon_buybox_share_pct_90d", type: "REAL" },
+    { name: "upc", type: "TEXT" },
+    { name: "supplier_score", type: "REAL" },
+    { name: "supplier_profit", type: "REAL" },
+    { name: "supplier_margin", type: "REAL" },
+    { name: "supplier_roi", type: "REAL" },
+    { name: "supplier_reason", type: "TEXT" },
+    { name: "upc_lookup_status", type: "TEXT" },
+    { name: "upc_lookup_reason", type: "TEXT" },
+    { name: "candidate_asins", type: "TEXT" },
   ];
 
   for (const column of requiredColumns) {
@@ -243,9 +258,18 @@ export function initDb(dbPath: string): void {
       promo_coupon_code TEXT,
       notes TEXT,
       lead_date TEXT,
+      upc TEXT,
       fba_fee REAL,
       fbm_fee REAL,
       referral_percent REAL,
+      supplier_score REAL,
+      supplier_profit REAL,
+      supplier_margin REAL,
+      supplier_roi REAL,
+      supplier_reason TEXT,
+      upc_lookup_status TEXT,
+      upc_lookup_reason TEXT,
+      candidate_asins TEXT,
       can_sell TEXT,
       sellability_status TEXT,
       sellability_reason TEXT,