feat: scaffold Django multi-tenant project with 5 of 9 apps

Phase 1 scaffolding: config/, core/, base models, AES-256-GCM phone encryption, enums mirror

apps.tenant: Tenant + Domain (django-tenants)

apps.org: 11 models (OrgUnit hierarchy, Staff, audit logs)

apps.account: 4 models (UserAccount as AUTH_USER_MODEL, login/password tracking)

apps.permission: 7 models (RBAC + overrides + datascope + append-only changelog)

apps.region: 5 models (District, BusinessArea, MetroLine, MetroStation, School)

All migrations generated, manage.py check passes

core/models/base.py

@@ -0,0 +1,71 @@
+import uuid
+
+from django.db import models
+from django.utils import timezone
+
+
+class UUIDPrimaryKeyModel(models.Model):
+    id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
+
+    class Meta:
+        abstract = True
+
+
+class TimeStampedModel(UUIDPrimaryKeyModel):
+    created_at = models.DateTimeField(auto_now_add=True, db_index=True)
+    updated_at = models.DateTimeField(auto_now=True)
+
+    class Meta:
+        abstract = True
+        ordering = ["-created_at"]
+
+
+class ActiveManager(models.Manager):
+    def get_queryset(self):
+        return super().get_queryset().filter(deleted_at__isnull=True)
+
+
+class SoftDeleteModel(TimeStampedModel):
+    deleted_at = models.DateTimeField(null=True, blank=True, db_index=True)
+
+    objects = ActiveManager()
+    all_objects = models.Manager()
+
+    def delete(self, using=None, keep_parents=False):
+        self.deleted_at = timezone.now()
+        self.save(update_fields=["deleted_at"])
+
+    def hard_delete(self):
+        super().delete()
+
+    def restore(self):
+        self.deleted_at = None
+        self.save(update_fields=["deleted_at"])
+
+    @property
+    def is_deleted(self):
+        return self.deleted_at is not None
+
+    class Meta:
+        abstract = True
+
+
+class AuditedModel(SoftDeleteModel):
+    created_by = models.ForeignKey(
+        "org.Staff",
+        null=True,
+        blank=True,
+        on_delete=models.SET_NULL,
+        related_name="%(app_label)s_%(class)s_created",
+        db_index=True,
+    )
+    updated_by = models.ForeignKey(
+        "org.Staff",
+        null=True,
+        blank=True,
+        on_delete=models.SET_NULL,
+        related_name="%(app_label)s_%(class)s_updated",
+    )
+
+    class Meta:
+        abstract = True