Add custom stats widgets and update API routing and CI pipeline integration

[MSalman6]

This pull request introduces a new "Custom Stat" widget to the home page stats section, allowing dynamic display of custom statistics based on a configurable JSON file. It adds both backend and frontend support for fetching and rendering these custom stats, and ensures proper integration with analytics and metadata systems. Additionally, a new GitHub Actions workflow is added for Docker image publishing.

Custom Stat Widget Feature:

• Added a new API route (app/api/custom-stat/route.ts) that reads from a custom-config.json file and fetches upstream data for each configured custom stat, supporting flexible stat configuration.
• Implemented the CustomStatWidget React component (client/slices/home/pages/index/stats/CustomStatWidget.tsx) to fetch the custom stat configs and display each stat as a widget, with support for nested JSON paths and icons.
• Integrated CustomStatWidget into the main stats grid on the home page (client/slices/home/pages/index/stats/Stats.tsx). [1] [2]

Analytics and Metadata Integration:

• Registered the /api/custom-stat route with analytics (client/shared/analytics/mixpanel/get-page-type.ts), Open Graph metadata (client/shared/metadata/get-page-og-type.ts), and page template/title systems (client/shared/metadata/templates/description.ts, client/shared/metadata/templates/title.ts) to ensure consistent tracking and SEO. [1] [2] [3] [4]

DevOps:

• Added a new GitHub Actions workflow (.github/workflows/docker-publish.yml) to build and publish Docker images for the project on pushes to the dmd branch.