Lohnt sich dein eigenes Runway?

Build me a thin video-generation workbench over hosted models, in place of
Runway. Requirements:

- A local web page on localhost:3300: Node + Express, a prompt box, a model
  picker, and a gallery of past generations.
- Generate via the Replicate API (token in .env) against current open video
  models (Wan/LTX/Hunyuan class). Pick one provider and stick to it; fal.ai
  only if it has a model Replicate lacks.
- Poll the job, download the mp4 to ~/generations/YYYY-MM-DD/, and record
  prompt, model, params, cost, and file path in SQLite (better-sqlite3).
- Image-to-video: upload a still and pass it as the conditioning frame.
- Show a month-to-date spend total computed from per-job cost so usage stays
  honest.
- No accounts, no telemetry; prompts and outputs stay local except the API
  calls themselves.
- Out of scope: editing timelines, inpainting, and anything realtime. Do not
  build model hosting or a job queue beyond simple polling.
- README: where to get the Replicate token, rough dollars per second of video
  on the default model, and a note that this rents models rather than replacing
  Runway, whose frontier video models and compute cannot be rebuilt solo.