Ensure PostgreSQL tables are created and data is migrated

This commit modifies the database connection logic to prioritize PostgreSQL, introduces a new PostgreSQL initialization script with table creation and test data, and refactors announcement storage to use a global instance.

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Replit-Commit-Session-Id: e437ffed-c31b-44eb-9fd5-b6f9faa8e7ce
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server/storage.ts

@@ -68,6 +68,7 @@ import {
 } from "@shared/schema";
 import { db } from "./db";
 import { eq, and, inArray, desc, sql, gte, lte, lt, or, isNull, isNotNull, asc } from "drizzle-orm";
+import { getAnnouncementStorage } from "./announcementStorage";
 
 
 export interface IStorage {