Arca 1.3.1: smoother onboarding

A small follow-up to 1.3.0.

✨ Onboarding

• The step buttons stay in view in a strip under the card, instead of covering the last field on small screens.
• The final check now grows into the finish animation.
• The welcome screen shows what's ready: transactions sorted, your needs / wants / savings plan, and the bills on Upcoming.

🛠 Housekeeping

• The README no longer shows broken screenshot images; the shots to add are listed in docs/screenshots.
• Uploaded profile photos are kept out of the repository.

🐳 Updating

damianeickhoff/arca:latest on Docker Hub. On Unraid, Check for updates in the Docker tab, then apply. Back up /data first.