Content Publishing Platform

Problem/Feature Description

A media company is building a content publishing platform backend with Node.js, TypeScript, and Express. The service uses PostgreSQL via the pg package. The database is accessible via a DATABASE_URL environment variable.

The platform needs to support:

• Creating an article with title, body, author_id, status (draft/published/archived), and tags (an array of strings). The author must exist in the authors table -- if they don't, creation should fail with a clear error.
• Publishing an article: sets status to "published" and published_at to the current time. If the article is already published, return a clear error.
• Bulk importing articles from a CSV ingest pipeline -- receives an array of 50-500 articles that must be written efficiently
• Searching articles by multiple tags (find articles matching ANY of the given tags)
• Listing articles filtered by multiple statuses (e.g. show "draft" and "published" but not "archived")
• Getting a single article by ID

Tables needed:

• authors: id (serial), name, email (unique), created_at
• articles: id (serial), title, body (text), author_id (FK to authors), status, tags (text[]), published_at (nullable), created_at, updated_at

Output Specification

Produce:

• db.ts -- Database connection module
• articles.ts -- Functions for all six operations listed above
• package.json -- With required dependencies
• migrations/001_create_tables.sql -- SQL migration for both tables

The code should be complete TypeScript with no placeholders or TODO comments.