Fix environment variable resolution for Stack compose deployments

[Copilot]

What is this PR about?

Stack compose deployments were failing to resolve environment-scoped variables (e.g., ${{environment.FOO}}), throwing "Invalid environment variable: environment.FOO". Docker-compose deployments worked correctly.

The getExportEnvCommand function (Stack-specific) was missing the third parameter when calling getEnviromentVariablesObject:

// Before - missing environment.env parameter
const envVars = getEnviromentVariablesObject(
  compose.env,
  compose.environment.project.env,
);

// After - now includes environment.env
const envVars = getEnviromentVariablesObject(
  compose.env,
  compose.environment.project.env,
  compose.environment.env,
);

This aligns Stack behavior with docker-compose, which already passed all three parameters.

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.

Issues related (if applicable)

Related to environment variable substitution in Stack compose type applications.

Screenshots (if applicable)

N/A - Backend logic change with test coverage added.

Original prompt

---

This section details on the original issue you should resolve

<issue_title>Unable to use envs of environment on Stack compose type application</issue_title>
<issue_description>### To Reproduce

1. Configure envs of environment

   FOO=bar

2. Create Compose application with Stack type

3. Configure service envs which uses env from environment

   FOO=${{environment.FOO}}

4. Deploy application

Current vs. Expected behavior

Current behaviour: error Invalid environment variable: environment.FOO

Expected behaviour: Envs being injected

Provide environment information

Operating System:
  OS: WSL2
  Arch: amd64

Dokploy version: v0.26.4

Which area(s) are affected? (Select all that apply)

Application, Docker Compose

Are you deploying the applications where Dokploy is installed or on a remote server?

Same server where Dokploy is installed

Additional context

This error only occurs when using the Stack type. The error does not occur when using the Docker Compose type.

The issue does not occur when using project envs.

Will you send a PR to fix it?

Maybe, need help</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes Unable to use envs of environment on Stack compose type application #3452

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