feat: add Mastodon service template

[maebahesioru]

Changes

Adds a one-click deployment template for Mastodon, the most widely used Fediverse / ActivityPub platform.

The template includes:

• web — Puma app server (port 3000)
• streaming — Node.js streaming API (port 4000)
• sidekiq — background job worker
• postgres:14-alpine — database (matches official docker-compose.yml)
• redis:7-alpine — cache/queue

SECRET_KEY_BASE and OTP_SECRET are auto-generated via SERVICE_PASSWORD_64_*. VAPID_PRIVATE_KEY and VAPID_PUBLIC_KEY must be generated manually (instructions in template comments). LOCAL_DOMAIN is required and permanent.

Issues

• Fixes

Category

• Bug fix
• Improvement
• New feature
• Adding new one click service
• Fixing or updating existing one click service

Preview

AI Assistance

• AI was NOT used to create this PR
• AI was used (please describe below)

If AI was used:

• Tools used: Kiro
• How extensively: Template structure verified against official mastodon/mastodon docker-compose.yml and .env.production.sample.

Testing

Verified against official Mastodon repository:

• Image names match ghcr.io/mastodon/mastodon:latest and ghcr.io/mastodon/mastodon-streaming:latest
• Environment variables match .env.production.sample
• PostgreSQL version matches official docker-compose.yml (postgres:14-alpine)
• Healthcheck endpoints match official compose (/health, /api/v1/streaming/health)
• SERVICE_PASSWORD_64_* used for SECRET_KEY_BASE and OTP_SECRET (128-char hex required by Mastodon)

Contributor Agreement

Important

• I have read and understood the contributor guidelines. If I have failed to follow any guideline, I understand that this PR may be closed without review.
• I have searched existing issues and pull requests (including closed ones) to ensure this is not a duplicate.
• I have tested all the changes thoroughly with a local development instance of Coolify and I am confident that they will work as expected when a maintainer tests them.