feat: add GitHub Actions workflow for direct Railway deploy and deploy scripts

[felipeofdev-ai]

Motivation

• Allow publishing the project to Railway directly from GitHub (manual dispatch or push to main) so users can deploy without running local commands while keeping the same validations (tests, clean git state, healthcheck).
• Make deploy flows explicit and cross-platform by documenting required secrets and providing both shell and PowerShell deploy scripts.

Description

• Add .github/workflows/deploy-railway.yml that installs the Railway CLI, optionally runs railway link using project/environment/service IDs from secrets, resolves PUBLIC_API_URL from the workflow input or secret, and runs ./scripts/deploy_real.sh.
• Add scripts/deploy_real.sh (Linux/macOS) and scripts/deploy_real.ps1 (PowerShell) which validate prerequisites, enforce RAILWAY_TOKEN, check for a clean Git state, install deps, run pytest -q, execute railway up --ci, detect the public URL and poll the /health endpoint until it returns HTTP 200.
• Update README.md and RAILWAY_DEPLOY.md with a new section describing how to run the deploy from GitHub Actions, a list of required optional secrets (RAILWAY_TOKEN, PUBLIC_API_URL, RAILWAY_PROJECT_ID, RAILWAY_ENVIRONMENT_ID, RAILWAY_SERVICE_ID), and examples for CLI and PowerShell usage.
• Keep the CI test job intact and trigger the deploy workflow on manual dispatch and push to main.

Testing

• Ran pytest -q, which succeeded with 24 passed, 6 warnings.
• Performed a shell syntax check bash -n scripts/deploy_real.sh, which returned OK.
• Parsed workflow YAML files with python using yaml.safe_load(...) to validate YAML correctness, which succeeded.
• Executed the repository-level validations (tests and syntax checks) as automated verification steps and they all passed.

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Codex Task