feat: customizable compose workdir

[jr-k]

What is this PR about?

Adds a per-compose-service Working Directory setting that controls the directory from which docker compose (or docker stack deploy) is launched. Previously, Dokploy always ran docker compose from the cloned repository root (<COMPOSE_PATH>/<appName>/code), which is a problem for monorepos and any compose file that relies on relative paths. With this change, users can point Dokploy at a subfolder of the repo and have all relative paths resolve from that subfolder.

The field is optional: empty value preserves the existing behavior.

Checklist

Before submitting this PR, please make sure that:

• You created a dedicated branch based on the canary branch.
• You have read the suggestions in the CONTRIBUTING.md file https://github.com/Dokploy/dokploy/blob/canary/CONTRIBUTING.md#pull-request
• You have tested this PR in your local instance. If you have not tested it yet, please do so before submitting. This helps avoid wasting maintainers' time reviewing code that has not been verified by you.

Issues related (if applicable)

Screenshots (if applicable)