Switch test suite from SQLite to PostgreSQL

[Copilot]

SQLite doesn't support certain JSON field queries used in production, making those code paths untestable. Aligns test environment with production PostgreSQL.

Changes

• readthedocs/settings/test.py — Replace SQLite with postgresql_psycopg2 for both default and telemetry databases; credentials via DB_USER/DB_PWD/DB_HOST env vars (defaults: docs_user/docs_pwd/localhost):

  "default": {
      "ENGINE": "django.db.backends.postgresql_psycopg2",
      "NAME": "test_docs_db",
      "USER": os.environ.get("DB_USER", "docs_user"),
      "PASSWORD": os.environ.get("DB_PWD", "docs_pwd"),
      "HOST": os.environ.get("DB_HOST", "localhost"),
      "PORT": "",
  },

• tox.ini — Add DB_USER, DB_PWD, DB_HOST to passenv so they propagate into the tox virtualenv.

• .circleci/config.yml — Add cimg/postgres:14.0 sidecar to tests, tests-search, and tests-proxito jobs; add a reusable wait-for-postgres command that polls readiness via pg_isready and explicitly creates the test_telemetry database (test_docs_db is created automatically via POSTGRES_DB); install postgresql-client in each affected job.

Generated by Copilot

[humitos]

Looks good so far... let's see if there are tests failing or not.

[humitos]

Suggested change

	- image: 'cimg/postgres:14.0'
	- image: 'cimg/postgres:16.3'

We are using version 16.3 locally, so we should use the same if it's available.

[humitos]

Same here.

[humitos]

Locally it runs in another container, so we need to use database as a host.

Suggested change

	"HOST": os.environ.get("DB_HOST", "localhost"),
	"PORT": "",
	},
	"telemetry": {
	"ENGINE": "django.db.backends.sqlite3",
	"NAME": os.path.join(self.SITE_ROOT, "telemetry.dev.db"),
	"ENGINE": "django.db.backends.postgresql_psycopg2",
	"NAME": "test_telemetry",
	"USER": os.environ.get("DB_USER", "docs_user"),
	"PASSWORD": os.environ.get("DB_PWD", "docs_pwd"),
	"HOST": os.environ.get("DB_HOST", "localhost"),
	"HOST": os.environ.get("DB_HOST", "database"),
	"PORT": "",
	},
	"telemetry": {
	"ENGINE": "django.db.backends.postgresql_psycopg2",
	"NAME": "test_telemetry",
	"USER": os.environ.get("DB_USER", "docs_user"),
	"PASSWORD": os.environ.get("DB_PWD", "docs_pwd"),
	"HOST": os.environ.get("DB_HOST", "database"),