feat(14-01): add PGlite test helper and generate initial PostgreSQL migration

- Rewrite tests/helpers/db.ts to use drizzle-orm/pglite with async createTestDb()
- Generate initial migration with 13 CREATE TABLE statements in drizzle-pg/
- Add drizzle-pg to biome ignore list (generated files)
- PGlite smoke test confirms migrations apply and seed works

tests/helpers/db.ts

@@ -1,21 +1,17 @@
-import { Database } from "bun:sqlite";
-import { drizzle } from "drizzle-orm/bun-sqlite";
-import { migrate } from "drizzle-orm/bun-sqlite/migrator";
+import { drizzle } from "drizzle-orm/pglite";
+import { migrate } from "drizzle-orm/pglite/migrator";
 import * as schema from "../../src/db/schema.ts";
 
-export function createTestDb() {
-	const sqlite = new Database(":memory:");
-	sqlite.run("PRAGMA foreign_keys = ON");
+export async function createTestDb() {
+	const db = drizzle({ schema });
 
-	const db = drizzle(sqlite, { schema });
-
-	// Apply all migrations to create tables
-	migrate(db, { migrationsFolder: "./drizzle" });
+	// Apply migrations from the new PostgreSQL migration directory
+	await migrate(db, { migrationsFolder: "./drizzle-pg" });
 
 	// Seed default Uncategorized category
-	db.insert(schema.categories)
-		.values({ name: "Uncategorized", icon: "package" })
-		.run();
+	await db
+		.insert(schema.categories)
+		.values({ name: "Uncategorized", icon: "package" });
 
 	return db;
 }