feat: restructure PostgreSQL setup with base variant

postgres/.env.example

@@ -1,4 +0,0 @@
-POSTGRES_USER=postgres
-POSTGRES_PASSWORD=postgres
-POSTGRES_DB=postgres
-POSTGRES_PORT=5432

postgres/000_extensions.sql

@@ -1,3 +0,0 @@
-CREATE EXTENSION IF NOT EXISTS citext;
-CREATE EXTENSION IF NOT EXISTS pg_trgm;
-CREATE EXTENSION IF NOT EXISTS pgcrypto;

postgres/Dockerfile

@@ -1,6 +0,0 @@
-FROM postgres:18-alpine
-
-COPY 000_extensions.sql /docker-entrypoint-initdb.d/
-
-HEALTHCHECK --interval=10s --timeout=5s --retries=5 \
-  CMD pg_isready -U ${POSTGRES_USER} -d ${POSTGRES_DB}

postgres/compose.yml

@@ -1,16 +0,0 @@
-services:
-  postgres:
-    # run `just build postgres` first
-    image: db-postgres:latest
-    restart: unless-stopped
-    environment:
-      POSTGRES_USER: ${POSTGRES_USER:-postgres}
-      POSTGRES_PASSWORD: ${POSTGRES_PASSWORD:-postgres}
-      POSTGRES_DB: ${POSTGRES_DB:-postgres}
-    ports:
-      - "${POSTGRES_PORT:-5432}:5432"
-    volumes:
-      - postgres-data:/var/lib/postgresql
-
-volumes:
-  postgres-data: