test(1013-01): add TestLegacyClassesRemoved.m contract guard (DIFF-03)

- New tests/suite/TestLegacyClassesRemoved.m (~34 LOC).
- Parameterized over the 11 legacy classes deleted across v2.0
  (Phase 1011: Threshold, CompositeThreshold, StateChannel,
  ThresholdRule, Sensor, SensorRegistry, ThresholdRegistry,
  ExternalSensorRegistry) and v2.1 (Phase 1013: EventDetector,
  IncrementalEventDetector, EventConfig).
- Asserts exist(ClassName, 'class') == 0 for each -- accidental
  re-introduction (revert, copy-paste, future contributor) fires a
  focused failure naming the leaking class.
- Auto-discovered by tests/run_all_tests.m via TestSuite.fromFolder
  -- no runner edit needed.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: HanSur94

tests/suite/TestLegacyClassesRemoved.m

@@ -0,0 +1,34 @@
+classdef TestLegacyClassesRemoved < matlab.unittest.TestCase
+%TESTLEGACYCLASSESREMOVED Regression-guard contract test for v2.1 deletion.
+%
+%   Asserts that the 11 legacy classes deleted across Phase 1011 (v2.0)
+%   and Phase 1013 (v2.1) are NOT reachable on the MATLAB path after
+%   install().  Re-introduction of any of these names -- by accidental
+%   git revert, careless copy-paste, or a future contributor unaware of
+%   the v2.0/v2.1 cleanup -- fires a fast, focused failure here.
+%
+%   This is a STATIC contract test, not a behavioral one.  It runs in
+%   ~milliseconds and adds no runtime cost to the suite.
+%
+%   See also TestGoldenIntegration (the v2.0 behavioral regression guard).
+
+    properties (TestParameter)
+        ClassName = {'EventDetector', 'IncrementalEventDetector', 'EventConfig', ...
+                     'Threshold', 'CompositeThreshold', 'StateChannel', 'ThresholdRule', ...
+                     'Sensor', 'SensorRegistry', 'ThresholdRegistry', 'ExternalSensorRegistry'};
+    end
+
+    methods (TestClassSetup)
+        function addPaths(testCase) %#ok<MANU>
+            addpath(fullfile(fileparts(mfilename('fullpath')), '..', '..'));
+            install();
+        end
+    end
+
+    methods (Test)
+        function classIsAbsent(testCase, ClassName)
+            testCase.verifyEqual(exist(ClassName, 'class'), 0, ...
+                sprintf('Legacy class %s should not be reachable; was deleted in Phase 1011 (v2.0) or Phase 1013 (v2.1).', ClassName));
+        end
+    end
+end