feat(complex): add apps.complex with 10 models and full-text search

- 10 models: Complex, ComplexAlias, ComplexBusinessArea, ComplexSchool, ComplexMetroStation, Building, RoomUnit, ComplexPhoto, ComplexAttachment, ComplexPriceTrend
- RunSQL migration: pg_trgm extension, gin_trgm_ops indexes, tsvector triggers for complex search_vector (from name/alias/address)
- Optimistic locking via version field on Complex
- 4 lock flags (lock_building/room/info/standard_room) per spec
- Adds ComplexPropertyUsageType + ComplexBuildingStructure enums
- manage.py check passes

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)
Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

apps/complex/models/__init__.py

@@ -0,0 +1,25 @@
+from apps.complex.models.complex import (
+    Building,
+    Complex,
+    ComplexAlias,
+    ComplexAttachment,
+    ComplexBusinessArea,
+    ComplexMetroStation,
+    ComplexPhoto,
+    ComplexPriceTrend,
+    ComplexSchool,
+    RoomUnit,
+)
+
+__all__ = [
+    "Building",
+    "Complex",
+    "ComplexAlias",
+    "ComplexAttachment",
+    "ComplexBusinessArea",
+    "ComplexMetroStation",
+    "ComplexPhoto",
+    "ComplexPriceTrend",
+    "ComplexSchool",
+    "RoomUnit",
+]