feat(01-01): define DB schema, configure Drizzle Kit, write seed script

- Created src/lib/db/schema.ts with users table (id, email, password_hash, created_at)
- Created src/lib/db/index.ts exporting db singleton via Drizzle + Neon HTTP driver
- Created drizzle.config.ts pointing to schema.ts with postgresql dialect
- Created scripts/seed.ts reading AGENT_EMAIL/AGENT_PASSWORD to create hashed user row
- Generated drizzle/0000_milky_black_cat.sql migration (committed per user decision)
- db:migrate and db:seed pending user Neon database setup

teressa-copeland-homes/drizzle.config.ts

@@ -0,0 +1,11 @@
+import "dotenv/config";
+import { defineConfig } from "drizzle-kit";
+
+export default defineConfig({
+  schema: "./src/lib/db/schema.ts",
+  out: "./drizzle",
+  dialect: "postgresql",
+  dbCredentials: {
+    url: process.env.DATABASE_URL!,
+  },
+});