fix(db): swap @neondatabase/serverless for postgres.js (local dev support)

Neon serverless driver requires remote WebSocket — incompatible with local
PostgreSQL. Replaced with postgres.js (drizzle-orm/postgres-js) in db/index.ts,
scripts/seed.ts, and drizzle.config.ts.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

teressa-copeland-homes/src/lib/db/index.ts

@@ -1,5 +1,5 @@
-import { drizzle } from "drizzle-orm/neon-http";
-import { neon } from "@neondatabase/serverless";
+import { drizzle } from "drizzle-orm/postgres-js";
+import postgres from "postgres";
 import * as schema from "./schema";
 
 type DrizzleDb = ReturnType<typeof createDb>;
@@ -9,8 +9,8 @@ function createDb() {
   if (!url) {
     throw new Error("DATABASE_URL environment variable is not set");
   }
-  const sql = neon(url);
-  return drizzle({ client: sql, schema });
+  const client = postgres(url);
+  return drizzle({ client, schema });
 }
 
 // Lazy singleton — created on first use, not at module load time