feat: add tests for import polling, login page, money utilities, and query keys

- Implemented tests for import polling functionality, ensuring correct behavior for active and terminal import statuses.
- Created tests for the login page, validating user interactions and error handling.
- Added unit tests for money utility functions, covering parsing, formatting, and summation of monetary values.
- Developed tests for query keys, ensuring proper scoping and invalidation roots.

chore: setup testing environment and configuration

- Added setup file for testing with Vitest and Testing Library.
- Configured TypeScript and Vite for the frontend project.
- Created Docker and Nginx configurations for local development and production environments.
- Established a PostgreSQL initialization script for setting up application roles.

docs: add README and environment configuration for infra

- Included README for the infra directory, detailing local development setup and service descriptions.
- Created an example environment configuration file for local development with placeholders for sensitive information.

backend/app/audit/models.py

@@ -0,0 +1,25 @@
+import uuid
+from typing import Any
+
+from sqlalchemy import JSON, ForeignKey, String, Uuid
+from sqlalchemy.orm import Mapped, mapped_column
+
+from app.db.base import Base, PkMixin, TimestampMixin
+
+
+class AuditEvent(Base, PkMixin, TimestampMixin):
+    """Append-only domain/security event. Never stores raw financial payloads."""
+
+    __tablename__ = "audit_events"
+    __table_args__ = (
+        {"comment": "Append-only audit trail; updates and deletes are blocked by trigger in PG."},
+    )
+
+    space_id: Mapped[uuid.UUID | None] = mapped_column(
+        Uuid, ForeignKey("financial_spaces.id", ondelete="SET NULL"), nullable=True, index=True
+    )
+    user_id: Mapped[uuid.UUID | None] = mapped_column(
+        Uuid, ForeignKey("users.id", ondelete="SET NULL"), nullable=True, index=True
+    )
+    event_type: Mapped[str] = mapped_column(String(64), nullable=False)
+    detail: Mapped[dict[str, Any] | None] = mapped_column(JSON, nullable=True)