Add v1 shortener: Bearer API, public 302, landing, and CI.

Standalone Django service so callers can mint links and phones get a 302.
Closes #1.

scripts/docker-entrypoint.sh

@@ -0,0 +1,56 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+cd /app/site
+
+wait_for_database() {
+  if [[ -z "${DATABASE_URL:-}" && -z "${DB_HOST:-}" ]]; then
+    return 0
+  fi
+
+  echo "Waiting for database..."
+  for _ in $(seq 1 30); do
+    if uv run python - <<'PY'
+import os
+import sys
+
+os.environ.setdefault("DJANGO_SETTINGS_MODULE", "shortener.settings")
+
+import django
+from django.db import connections
+from django.db.utils import OperationalError
+
+django.setup()
+
+try:
+    connections["default"].ensure_connection()
+except OperationalError:
+    sys.exit(1)
+PY
+    then
+      echo "Database is ready."
+      return 0
+    fi
+    sleep 2
+  done
+
+  echo "Database did not become ready in time." >&2
+  exit 1
+}
+
+wait_for_database
+
+uv run python manage.py migrate --noinput
+
+# Local compose defaults to DJANGO_ENV=dev: runserver + source bind-mount → hot reload.
+# Prod/beta images keep gunicorn (no file watch).
+if [[ "${DJANGO_ENV:-}" == "dev" || "${DJANGO_USE_RUNSERVER:-}" == "true" ]]; then
+  echo "Starting Django runserver (auto-reload on)."
+  exec uv run python manage.py runserver "${GUNICORN_BIND:-0.0.0.0:8000}"
+fi
+
+uv run python manage.py collectstatic --noinput
+
+exec uv run gunicorn shortener.wsgi:application \
+  --bind "${GUNICORN_BIND:-0.0.0.0:8000}" \
+  --workers "${GUNICORN_WORKERS:-2}"