Initial commit: Maskan CRM backend

Independent FastAPI backend for Maskan CRM.

Owns contacts, organizations, leads, pipelines, activities, products,
quotes, users, permissions, audit records and first-party integration
credentials, with Alembic migrations against PostgreSQL.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

.env.example

@@ -0,0 +1,18 @@
+MASKAN_CRM_ENV=development
+MASKAN_CRM_MODE=standalone
+MASKAN_CRM_CORS_ORIGINS=http://127.0.0.1:5174,http://localhost:5174
+MASKAN_CRM_JWT_SECRET=replace-with-a-random-value-at-least-32-characters
+MASKAN_CRM_ACCESS_TOKEN_MINUTES=30
+
+DB_HOST=127.0.0.1
+DB_PORT=5433
+DB_NAME=maskan_crm
+DB_USER=postgres
+DB_PASSWORD=postgres
+DB_SSLMODE=disable
+
+MASKAN_CRM_BOOTSTRAP_WORKSPACE=maskan
+MASKAN_CRM_BOOTSTRAP_COMPANY=Maskan Technologies
+MASKAN_CRM_BOOTSTRAP_ADMIN_EMAIL=owner@example.com
+MASKAN_CRM_BOOTSTRAP_ADMIN_PASSWORD=replace-before-first-run
+MASKAN_CRM_SEED_DEMO=true