chore: harden Dockerfile by running as non-root user and updating R package installation process

refactor: migrate mapping functionality from Leaflet to mapgl and sf, updating dependencies, UI, and server logic for new basemap options.

feat: Implement Excel data export using `writexl` and update download filename format.

build: add httr R package dependency to Dockerfile.

feat: Initial setup for JMA Weather Explorer, including README, Dockerfile, and Hugging Face deployment workflow.