chore(deploy): remove Dokploy, switch to native docker compose + Gitea Actions

- Remove Dokploy deploy jobs from GitHub CI workflow (test + build only)
- Add .gitea/workflows/ci.yml (Gitea Actions: lint, tests, docker build verify)
- Rewrite deploy.sh: set -euo pipefail, mandatory .env.<env>, --env-file,
  healthcheck on /api/health with log dump on failure
- Delete Dokploy-specific docs (3 files), update references in README,
  TODO.md, architecture.md, guides, dev plan
- Remove DOKPLOY_* env vars from proto/.env.local

GITHUB-INTEGRATION.md

@@ -159,10 +159,8 @@ Daily at 9 AM UTC
 ### **Required GitHub Secrets:**
 ```bash
 LINEAR_API_KEY=your_linear_api_key
-DOKPLOY_STAGING_WEBHOOK=https://staging.webhook.url
-DOKPLOY_PROD_WEBHOOK=https://prod.webhook.url  
-DOKPLOY_TOKEN=your_dokploy_token
 ```
+> ⚠️ Deploy nem történik CI-ből — natív docker compose (`deploy.sh`) a szerveren.
 
 ### **Environment Variables:**
 ```bash