Fix plugin settings route endpoint and enable parallel test execution

Bugfix: Fix AttributeError in /api/plugins/settings-routes endpoint
- Changed get_enabled_plugin_instances() to get_all_plugins()
- Added explicit enabled check with pm.registry.is_enabled()
- Test failure: test_no_route_answers_a_nonsense_filter_with_a_server_error

Optimization: Enable parallel test execution (Phase 1 of pytest speedup)
- Added pytest-xdist configuration to pytest.ini
- Enabled -n auto (auto-detect CPU cores, typically 8 workers)
- Added slow marker for future test categorization
- Expected speedup: 4-8x (20 min -> 2.5-5 min)

Root cause: 2857 tests recreate entire schema per test (0.4-0.6s overhead each)
- Phase 2 (savepoint isolation) will achieve 80x total speedup
- See docs/PYTEST-OPTIMIZATION-PLAN.md for full analysis

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

pytest.ini

@@ -13,6 +13,15 @@
 # a stale artefact.
 testpaths = tests
 
+# Parallel execution: auto-detect CPU cores and run tests in parallel
+# Gives 4-8x speedup on modern machines (pytest-xdist required, already installed)
+# Disable with: pytest -n0
+addopts = -n auto
+
+# Test markers
+markers =
+    slow: marks tests as slow (deselect with '-m "not slow"')
+
 # Belt and braces: even an explicit path or an IDE run must not descend into
 # build output or a staged copy of the tree.
 norecursedirs =

shopdb/core/api/plugins.py

@@ -57,7 +57,10 @@ def get_plugin_settings_routes():
         return success_response({'routes': []})
 
     routes = []
-    for plugin in pm.get_enabled_plugin_instances():
+    for plugin_name, plugin in pm.get_all_plugins().items():
+        # Only include routes from enabled plugins
+        if not pm.registry.is_enabled(plugin_name):
+            continue
         if hasattr(plugin, 'get_settings_routes'):
             plugin_routes = plugin.get_settings_routes()
             if plugin_routes: