Can I vibecode Later?

Build me a visual social post planner to replace Later. Requirements:

- Python 3.12 + FastAPI with Jinja2 templates and HTMX. `uv run planner` serves http://localhost:4860
  (admin) and runs a publish worker in the same process that checks for due posts every 30 seconds.
- Storage: SQLite via SQLAlchemy in ./data/planner.db and files in ./data/media/. Tables: media
  (file, kind, width, height, tags, alt text), posts (caption, ordered media ids, networks,
  scheduled_at in UTC, status draft / scheduled / publishing / published / failed, result URL per network).
- Media library: upload JPEG, PNG and MP4 by drag and drop, Pillow thumbnails, tag and search. On
  upload, warn when a file breaks a network rule: Instagram images must be JPEG, Reels need vertical video.
- Planner: a month calendar plus a three-column preview of the Instagram grid that mixes published
  posts (read back through the API) with scheduled ones. Drag a card to change its date or grid
  position. Once 30 posts are published, rank weekday and hour slots by engagement per reach from the
  Insights API and mark the top three; with fewer posts show "not enough data".
- One adapter interface, publish(post) returning the post URL, and three adapters: Instagram (the
  Instagram API with Instagram Login: create a media container, poll until it is ready, then publish;
  single image, carousel of up to 10, Reels), Bluesky (`atproto`, app password) and Mastodon
  (instance URL and access token). Set status to publishing before calling a network and never retry
  after a container was published; otherwise retry 3 times (1, 5 and 30 minutes) and show the error.
- Instagram setup: a Meta developer app in development mode with your own account added as a tester.
  Store the long-lived token encrypted (`cryptography` Fernet, key in .env) and refresh it before day
  60. Instagram fetches media from a public URL, so serve /media/<random-name> and the link-in-bio
  page on a second port (4861) and expose only that one through a tunnel.
- Link in bio: a public page at /links on port 4861 with ordered buttons edited in the admin and a
  click counter per button stored in SQLite.
- Single user: one password in .env. No accounts, no telemetry, local-first. The only outbound calls
  are to the three networks.
- Out of scope: TikTok, Pinterest, YouTube, LinkedIn, Stories, a social inbox, team approvals, AI captions.
- README: creating the Meta app and adding yourself as a tester, the tunnel for port 4861, and a
  warning that Meta's permissions and publishing limits change (check content_publishing_limit).

Opens your agent with the prompt filled in, you press enter. Or copy it and paste it into an empty folder.