Test dashboard: full menu system, all-service tests, filtering

- Run tests for all 10 services via per-service pytest subprocesses
- Group results by service with section headers
- Clickable summary cards filter by outcome (passed/failed/errors/skipped)
- Service filter nav using ~nav-link buttons in menu bar
- Full menu integration: ~header-row + ~header-child + ~menu-row
- Show logo image via cart-mini rendering
- Mount full service directories in docker-compose for test access
- Add 24 unit test files across 9 services

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

cart/tests/test_total.py

@@ -0,0 +1,47 @@
+"""Unit tests for cart total calculations."""
+from __future__ import annotations
+
+from decimal import Decimal
+from types import SimpleNamespace
+
+import pytest
+
+from cart.bp.cart.services.total import total
+
+
+def _item(special=None, regular=None, qty=1):
+    return SimpleNamespace(
+        product_special_price=special,
+        product_regular_price=regular,
+        quantity=qty,
+    )
+
+
+class TestTotal:
+    def test_empty_cart(self):
+        assert total([]) == 0
+
+    def test_regular_price_only(self):
+        result = total([_item(regular=10.0, qty=2)])
+        assert result == Decimal("20.0")
+
+    def test_special_price_preferred(self):
+        result = total([_item(special=5.0, regular=10.0, qty=1)])
+        assert result == Decimal("5.0")
+
+    def test_none_prices_excluded(self):
+        result = total([_item(special=None, regular=None, qty=1)])
+        assert result == 0
+
+    def test_mixed_items(self):
+        items = [
+            _item(special=5.0, qty=2),   # 10
+            _item(regular=3.0, qty=3),   # 9
+            _item(),                      # excluded
+        ]
+        result = total(items)
+        assert result == Decimal("19.0")
+
+    def test_quantity_multiplication(self):
+        result = total([_item(regular=7.5, qty=4)])
+        assert result == Decimal("30.0")