Adds a prices controller that fetches DK1/DK2 hourly spot prices via the
Energi Data Service API, stores them in PostgreSQL, and displays today's
and tomorrow's DK1 prices on the home page in øre/kWh. An HTMX "Refresh
Prices" button triggers the fetch-and-display cycle.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>