feat: implement full admin panel with dashboard, user management, and platform settings

Adds complete super_admin panel with 9 pages and account owner categories page.
Backend includes 5 new DB tables, ~25 API endpoints, settings manager with
in-memory cache, and 29 integration tests. Frontend includes reusable admin
components (DataTable, Pagination, ActionMenu, etc.) with code-split lazy loading.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

backend/tests/test_admin_audit_logs.py

@@ -0,0 +1,76 @@
+"""Integration tests for admin audit log endpoints."""
+
+import pytest
+from httpx import AsyncClient
+
+
+class TestAdminAuditLogs:
+
+    @pytest.mark.asyncio
+    async def test_list_audit_logs(
+        self, client: AsyncClient, admin_auth_headers: dict, test_user: dict
+    ):
+        """List audit logs with pagination."""
+        # Generate some audit activity first (e.g., admin listing users creates no audit,
+        # but we can create a tree to generate audit data)
+        response = await client.get(
+            "/api/v1/admin/audit-logs", headers=admin_auth_headers
+        )
+        assert response.status_code == 200
+        data = response.json()
+        assert "items" in data
+        assert "total" in data
+        assert "page" in data
+        assert "per_page" in data
+
+    @pytest.mark.asyncio
+    async def test_filter_audit_logs_by_action(
+        self, client: AsyncClient, admin_auth_headers: dict
+    ):
+        """Filter audit logs by action."""
+        response = await client.get(
+            "/api/v1/admin/audit-logs?action=tree.create",
+            headers=admin_auth_headers,
+        )
+        assert response.status_code == 200
+
+    @pytest.mark.asyncio
+    async def test_filter_audit_logs_by_resource_type(
+        self, client: AsyncClient, admin_auth_headers: dict
+    ):
+        """Filter audit logs by resource_type."""
+        response = await client.get(
+            "/api/v1/admin/audit-logs?resource_type=tree",
+            headers=admin_auth_headers,
+        )
+        assert response.status_code == 200
+
+    @pytest.mark.asyncio
+    async def test_filter_audit_logs_by_date_range(
+        self, client: AsyncClient, admin_auth_headers: dict
+    ):
+        """Filter audit logs by date range."""
+        response = await client.get(
+            "/api/v1/admin/audit-logs?date_from=2020-01-01T00:00:00Z&date_to=2030-12-31T23:59:59Z",
+            headers=admin_auth_headers,
+        )
+        assert response.status_code == 200
+
+    @pytest.mark.asyncio
+    async def test_export_audit_logs_csv(
+        self, client: AsyncClient, admin_auth_headers: dict
+    ):
+        """Export audit logs as CSV."""
+        response = await client.get(
+            "/api/v1/admin/audit-logs/export", headers=admin_auth_headers
+        )
+        assert response.status_code == 200
+        assert "text/csv" in response.headers.get("content-type", "")
+
+    @pytest.mark.asyncio
+    async def test_non_admin_cannot_access(
+        self, client: AsyncClient, auth_headers: dict
+    ):
+        """Non-admin gets 403."""
+        response = await client.get("/api/v1/admin/audit-logs", headers=auth_headers)
+        assert response.status_code == 403