docs: [#26] fix Docker Compose environment configuration example and improve formatting

- Correct ADR-007 container configuration example to show actual --env-file usage
- Fix Docker Compose example from incorrect env_file property to correct command-line flag
- Improve ADR table formatting in copilot instructions for better readability
- Remove trailing spaces and minor formatting improvements

Author: josecelano

.github/copilot-instructions.md

@@ -186,14 +186,14 @@ torrust-tracker-demo/
 
 Key design decisions are documented in `docs/adr/`. Contributors should review relevant ADRs when working on related features:
 
-| ADR                                                                                 | Title                               | Description                                                |
-| ----------------------------------------------------------------------------------- | ----------------------------------- | ---------------------------------------------------------- |
-| [ADR-001](../docs/adr/001-makefile-location.md)                                     | Makefile Location                   | Why the main Makefile is at repository root                |
-| [ADR-002](../docs/adr/002-docker-for-all-services.md)                               | Docker for All Services             | Why we use Docker for all services including UDP tracker   |
-| [ADR-003](../docs/adr/003-use-mysql-over-mariadb.md)                                | Use MySQL Over MariaDB              | Database backend selection rationale                       |
-| [ADR-004](../docs/adr/004-configuration-approach-files-vs-environment-variables.md) | Configuration Approach              | Files vs environment variables for configuration           |
-| [ADR-005](../docs/adr/005-sudo-cache-management-for-infrastructure-operations.md)   | Sudo Cache Management               | Managing sudo credentials during infrastructure operations |
-| [ADR-006](../docs/adr/006-ssl-certificate-generation-strategy.md)                   | SSL Certificate Generation Strategy | Approach for SSL certificate management                    |
+| ADR                                                                                 | Title                                    | Description                                                           |
+| ----------------------------------------------------------------------------------- | ---------------------------------------- | --------------------------------------------------------------------- |
+| [ADR-001](../docs/adr/001-makefile-location.md)                                     | Makefile Location                        | Why the main Makefile is at repository root                           |
+| [ADR-002](../docs/adr/002-docker-for-all-services.md)                               | Docker for All Services                  | Why we use Docker for all services including UDP tracker              |
+| [ADR-003](../docs/adr/003-use-mysql-over-mariadb.md)                                | Use MySQL Over MariaDB                   | Database backend selection rationale                                  |
+| [ADR-004](../docs/adr/004-configuration-approach-files-vs-environment-variables.md) | Configuration Approach                   | Files vs environment variables for configuration                      |
+| [ADR-005](../docs/adr/005-sudo-cache-management-for-infrastructure-operations.md)   | Sudo Cache Management                    | Managing sudo credentials during infrastructure operations            |
+| [ADR-006](../docs/adr/006-ssl-certificate-generation-strategy.md)                   | SSL Certificate Generation Strategy      | Approach for SSL certificate management                               |
 | [ADR-007](../docs/adr/007-two-level-environment-variable-structure.md)              | Two-Level Environment Variable Structure | Security-focused separation of infrastructure and container variables |
 
 ## 🛠️ Development Workflow

docs/adr/007-two-level-environment-variable-structure.md

@@ -162,19 +162,18 @@ envsubst < "infrastructure/config/templates/docker-compose.env.tpl" > "applicati
 
 ### For Container Configuration
 
-```yaml
-# docker-compose.yaml
-services:
-  tracker:
-    env_file: .env  # Only contains container-relevant variables
-    environment:
-      - TRACKER_ADMIN_TOKEN=${TRACKER_ADMIN_TOKEN}
+```bash
+# Docker Compose command (in deploy-app.sh)
+docker compose --env-file /var/lib/torrust/compose/.env up -d
+
+# The .env file contains only container-relevant variables
+# and is passed to Docker Compose via the --env-file flag
 ```
 
 ## Benefits
 
 1. **Security**: Reduced container attack surface
-2. **Clarity**: Clear separation between infrastructure and application concerns  
+2. **Clarity**: Clear separation between infrastructure and application concerns
 3. **Maintainability**: Easier to understand what variables are used where
 4. **Flexibility**: Can generate different container environments from same base
 5. **Compliance**: Aligns with twelve-factor configuration principles