feat: deploy to Dokploy on release alongside Heroku

[sebawebber]

Summary

• Adds a Deploy on Dokploy step to release.yml after the existing Heroku container:release
• Keeps the same tag-triggered GoReleaser flow; Dokploy pulls the freshly published pgconfig/api:latest image
• Documents the new GitHub Actions secrets in AGENTS.md

Required setup (before merge)

1. Dokploy application

Configure the application with Source Type: Docker (not GitHub build):

Field	Value
Docker Image	pgconfig/api:latest
Environment	PORT=3000
Domain port	3000

2. GitHub repository secrets

Add in Settings → Secrets and variables → Actions:

Secret	Example	Description
DOKPLOY_API_URL	https://dokploy.example.com	Base URL, no trailing slash
DOKPLOY_API_KEY	dkp_live_...	API key from Dokploy profile
DOKPLOY_APP_ID	cm5r8k9p00001xyz	Application ID from Dokploy

To find the application ID:

curl -s 'https://dokploy.example.com/api/project.all' \
  -H 'x-api-key: YOUR_KEY' | jq

Release flow after merge

git tag vX.Y.Z && git push origin vX.Y.Z
  → GoReleaser builds and pushes images
  → Heroku container:release web
  → Dokploy application.deploy (pulls pgconfig/api:latest)

Test plan

• Add the three Dokploy secrets to the repository
• Confirm Dokploy app uses Docker source with pgconfig/api:latest
• Create a test tag and verify both Heroku and Dokploy deploy succeed
• Hit /v1/tuning/list-environments on both endpoints