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>

market/tests/test_registry.py

@@ -0,0 +1,58 @@
+"""Unit tests for product registry utilities."""
+from __future__ import annotations
+
+import pytest
+
+from market.scrape.product.registry import merge_missing
+
+
+class TestMergeMissing:
+    def test_fills_empty_dict(self):
+        dst = {}
+        merge_missing(dst, {"a": 1, "b": "hello"})
+        assert dst == {"a": 1, "b": "hello"}
+
+    def test_existing_value_not_overwritten(self):
+        dst = {"a": "original"}
+        merge_missing(dst, {"a": "new"})
+        assert dst["a"] == "original"
+
+    def test_none_overwritten(self):
+        dst = {"a": None}
+        merge_missing(dst, {"a": "filled"})
+        assert dst["a"] == "filled"
+
+    def test_empty_string_overwritten(self):
+        dst = {"a": ""}
+        merge_missing(dst, {"a": "filled"})
+        assert dst["a"] == "filled"
+
+    def test_empty_list_overwritten(self):
+        dst = {"a": []}
+        merge_missing(dst, {"a": [1, 2]})
+        assert dst["a"] == [1, 2]
+
+    def test_empty_dict_overwritten(self):
+        dst = {"a": {}}
+        merge_missing(dst, {"a": {"key": "val"}})
+        assert dst["a"] == {"key": "val"}
+
+    def test_zero_not_overwritten(self):
+        dst = {"a": 0}
+        merge_missing(dst, {"a": 42})
+        assert dst["a"] == 0
+
+    def test_false_not_overwritten(self):
+        dst = {"a": False}
+        merge_missing(dst, {"a": True})
+        assert dst["a"] is False
+
+    def test_none_src(self):
+        dst = {"a": 1}
+        merge_missing(dst, None)
+        assert dst == {"a": 1}
+
+    def test_new_keys_added(self):
+        dst = {"a": 1}
+        merge_missing(dst, {"b": 2})
+        assert dst == {"a": 1, "b": 2}