Replace Publer?

Build a personal replacement for Publer in an empty repository.
Use Next.js 15, TypeScript, PostgreSQL, Drizzle ORM, and one official social-platform API; do not offer alternative stacks.
The core loop is: draft and schedule posts across a small set of networks, preview them accurately, publish through one official API, maintain reusable media, and retain a searchable content calendar.
Make the first run work locally with one documented command.
Store all user data locally by default and make export straightforward.
Put secrets in .env, ship .env.example, and never commit credentials.
Support drafts, scheduled times, queues, campaigns, tags, and a weekly calendar.
Connect exactly one social network using its documented OAuth flow.
Validate character, media, aspect-ratio, and file-size limits before scheduling.
Publish through an idempotent background job with retries and clear failure states.
Store platform post identifiers and refresh publication status without scraping.
Add reusable snippets, local media storage, CSV export, and a token reconnect flow.
Include clear empty, loading, success, and recoverable error states.
Add input validation, safe filenames, and graceful handling of unavailable APIs.
Write focused tests for the core transformation and one end-to-end happy path.
Create a README with setup, architecture, permissions, data location, and backup steps.
Do not add accounts, billing, telemetry, analytics, or a hosted control plane.
Deliberately leave out unofficial automation or scraping.
Deliberately leave out multi-network inbox and social listening.
Deliberately leave out agency approvals, white labelling, and enterprise reporting.
Finish by running the tests and listing the exact commands used.