Remove hardcoded port ENV var from Dockerfile

[Copilot]

ENV DevOidcToolkit__Port=8080 in the Dockerfile took precedence over config.json, making file-based port configuration silently ignored.

Changes

• Dockerfile: Remove ENV DevOidcToolkit__Port; retain ENV DevOidcToolkit__Address=0.0.0.0 (required for Docker networking); update EXPOSE and HEALTHCHECK to port 80 (the application default)
• README / docs: Update docker run examples from -p 8080:8080 → -p 8080:80 to reflect the container now listening on port 80 by default
• Example JSON configs: Update example "Port" values from 8080 to 80 to match the application default
• CHANGELOG: Added a breaking change entry noting the Docker default port change from 8080 to 80

Users who need a custom port can now set it via config.json or an explicit -e DevOidcToolkit__Port=... without it being silently overridden.

⚠️ Breaking Change: Docker port mappings must be updated from -p 8080:8080 to -p 8080:80.

[jthomperoo]

This needs a changelog update, noting it's a breaking change.

[Copilot]

This needs a changelog update, noting it's a breaking change.

Added a breaking change entry to the [Unreleased] section of the changelog in d2519d7, noting the Docker default port change from 8080 to 80 and linking to the issue.

[jthomperoo]

Testing this for Docker we still need to bind Address to 0.0.0.0 for Docker

[Copilot]

Testing this for Docker we still need to bind Address to 0.0.0.0 for Docker

Re-added ENV DevOidcToolkit__Address=0.0.0.0 to the Dockerfile in daf2d46 — only ENV DevOidcToolkit__Port=8080 is removed. The address binding remains so the app is reachable from outside the container.