docs: Clarify setup of Projects

[mmartinortiz]

This PR proposes a small change on the documentation to clarify that Projects are only available if AGENT_MODE is set to true. After using the docker-compose.yaml example, I did not see any project. It took me some time to find on the documentation that the variable AGENT_MODE needs to be set.

[kmendell]

Thanks, but for the main server this is incorrect, AGENT_MODE is only for the remote agents. UI_CONFIGURATION_DISABLED is the same thing which would allow all of the settinsg to be overidden by the env. Agent mode disabled more than just the UI configuration.

[mmartinortiz]

If the documentation is correct as it is now, then I'm missing something.

Small example to reproduce what I'm experiencing:

services:
  arcane:
    image: ghcr.io/getarcaneapp/arcane:latest
    container_name: arcane
    ports:
      - "3552:3552"
    volumes:
      - /var/run/docker.sock:/var/run/docker.sock
      - arcane-data:/app/data
      - /path/to/projects:/path/to/projects
    environment:
      - APP_URL=http://localhost:3552
      - PUID=1000
      - PGID=1000
      - ENCRYPTION_KEY=xxx
      - JWT_SECRET=xxx
    restart: unless-stopped

volumes:
  arcane-data:

This is the same compose file than in the documentation. In my local example I'm using secrets generated with arcane secrets as suggested in the docs. Despite in my local machine I have used a real folder with valid compose files that accessible by my user, here I used again dummy values.

The volume is correctly mounted in the container. If I access the container and check the folder with something like ls /path/to/projects, the structure of my projects is shown.

With that setup, my "projects" are empty. Only after adding the environment variables PROJECTS_DIRECTORY=/path/to/projects and either AGENT_MODE=true or UI_CONFIGURATION_DISABLE=true, the projects are shown.

I realize now that my pull request is incomplete and should mention PROJECTS_DIRECTORY, but before I update it, I just want to check with you why my setup fails when following the docs.

[kmendell]

I belive there is a bug with the environment overide loading, there are certain vaariables that are allowed even without AGENT_MODE or th ui disabled, i will look into it, and get back to you to make sure.

[kmendell]

This should be fixed on the main branch now. Thank you for you contribution though!