Buffer

Build me a personal social post scheduler to replace Buffer. Requirements: - Node + Express + better-sqlite3; a localhost page with a compose box, image attach, and the queue ordered by send time. - Two targets only: Mastodon (access token) and Bluesky (app password via @atproto/api), creds in .env. One small adapter file per network so a third is addable later, but scaffold nothing I don't use. - Buffer-style slots: I define posting times (say weekdays 09:00 and 17:00 in my timezone) and new posts fill the next free slot; a post can also be pinned to an exact datetime. - A node-cron tick every minute publishes due posts, marks each row sent or failed, retries failures 3 times with backoff, and marks before sending so nothing ever double-posts. - Per-network character counter in the composer; attached images stored in media/ next to the database. - A history page of the last 100 sent posts linking to the live posts. - Runs on my always-on box; localhost only, no accounts, no telemetry. - Out of scope: X, Instagram, and LinkedIn (paid, approval-gated, or hostile APIs, say so in the README), analytics, and rich post previews. - README: getting a Mastodon access token and a Bluesky app password.