fix: serve static files in production via deploy.sh

[emidiovaleretto]

Context

In production (DEBUG=False) Django doesn't serve static files automatically.
The DRF browsable API and admin were rendering without CSS. WhiteNoise was
already configured (middleware + storage), but collectstatic was never run.

What

• Add a deploy.sh script that runs collectstatic before starting gunicorn
• Point the Dockerfile's CMD to the script
• Use ${PORT} so the bind works both on Railway (injected PORT) and locally
• Ignore the generated staticfiles/ directory in git

Why

Static collection must happen at container start, not build time, because the
production settings require environment variables that only exist at runtime.
Running it in deploy.sh (with set -e to fail fast, and exec for proper
signal handling) keeps the startup sequence explicit and easy to extend.

How it works

• deploy.sh: set -e → collectstatic --noinput → exec gunicorn
• WhiteNoise serves the collected files (already configured via
  CompressedManifestStaticFilesStorage)

How to verify

Tested locally simulating production (DEBUG=False, gunicorn via the script):
the DRF browsable API renders with CSS. After merge, confirm the same at
api.simlog.app.br/api/auth/register/.