Dockerize scha + Gitea CI/CD auto-deploy via server-infra (#21)

## Summary
- Dockerize SCHA Wheaton (uv packaging, Dockerfile, compose, entrypoint) and move secrets/DB config to env-driven `scha/settings/`.
- Add Gitea Actions: unit tests on push/PR to `master`, auto-deploy on green master push via `server-infra/scripts/deploy.sh --app scha --env prod`.
- Prod compose uses shared external Postgres only (no bundled DB); control-node secret template at `.env.prod.example`.

Closes #19 (Part A). Depends on companion server-infra PR for catalog/host_apps registration.

## Test plan
- [ ] `uv sync --frozen` + `DJANGO_ENV=dev DJANGO_SECRET_KEY=test uv run python manage.py check`
- [ ] `docker compose build` succeeds locally
- [ ] `docker compose up` serves app against bundled Postgres
- [ ] `./scripts/validate-env.sh ~/Documents/secrets/scha/scha_prod.env` passes
- [ ] After merge + server-infra catalog live: push to master runs Unit Tests then Deploy

Reviewed-on: #21

pyproject.toml

@@ -0,0 +1,25 @@
+[project]
+name = "scha"
+version = "0.1.0"
+description = "Django site for SCHA Wheaton"
+readme = "README.md"
+requires-python = ">=3.12"
+dependencies = [
+    "django>=5.2,<6",
+    "django-phonenumber-field>=8.1.0",
+    "django-recaptcha>=4.1.0",
+    "gunicorn>=23.0.0",
+    "phonenumbers>=9.0.0",
+    "psycopg2-binary>=2.9.10",
+    "requests>=2.32.0",
+    "stripe>=12.0.0",
+    "whitenoise>=6.9.0",
+]
+
+[dependency-groups]
+dev = [
+    "pre-commit>=4.1.0",
+]
+
+[tool.uv]
+package = false