Fix production deployment configuration

[Copilot]

Production deployment was broken due to non-existent Go version and incomplete nginx configuration.

Changes

• server/Dockerfile: Fixed golang:1.25-alpine → golang:1.23-alpine (1.25 doesn't exist). Added ca-certificates and git to build stage for HTTPS module downloads.

• server/go.mod: Fixed go 1.25.2 → go 1.24.0 to match actual Go releases.

• nginx-production.conf: Completed empty configuration with reverse proxy setup:

  upstream backend { server localhost:8080; }
  upstream frontend { server localhost:5173; }
  
  location /api { proxy_pass http://backend; }
  location /ws { proxy_pass http://backend; }  # WebSocket with 24h timeout
  location / { proxy_pass http://frontend; }

  Added standard proxy headers, 50MB upload limit, and WebSocket upgrade support.

Original prompt

We Should fix production side of our project

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