Add Docker image setup

[adrunkhuman]

Summary

• Add a Dockerfile that runs the packaged pogodapp launcher with uv-managed production dependencies.
• Add a .dockerignore that keeps local caches, virtualenvs, and generated climate data out of the image context.
• Document local Docker build/run commands and persistent /app/data usage.

Validation

• ty type checker passed via commit hook.
• pytest passed via commit hook.