fix: flaky e2e tests, performance threshold, aiohttp/coverage improvements (#134)

* fix(deps): bump aiohttp >=3.9.0 → >=3.13.4, align black line-length, add coverage tests

Security:
- aiohttp>=3.13.4 closes 10 CVEs (CVE-2026-34513 through -34525 and GHSA variants)

Config:
- [tool.black] line-length 88 → 120 to match ruff (eliminates formatter conflict)

Tests:
- tests/test_finder_new_coverage.py: 40 new tests for apps/finder.py
  critical paths (get_applications, get_applications_from_system_profiler,
  batch error handling, rate limiter, async fallback, progress config)
  finder.py coverage: 69.9% → 82.4% (+12.5 pp)
- tests/test_comparator_coverage.py: 56 new tests for version/comparator.py
  uncovered branches (_compare_base_versions, _compare_build_numbers,
  _compare_prerelease, _apply_version_truncation, get_version_info, etc.)
  comparator.py coverage: 86.3% → 95.0% (+8.7 pp)

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

* test: fix flaky e2e tests and add exceptions/error_codes coverage

- Fix 3 flaky TestEndToEndIntegration tests that failed with seed
  3927212083: add autouse fixture to clear apps.finder.get_homebrew_casks
  lru_cache between tests; patch get_homebrew_casks at the handler
  import site in test_auto_updates_management_workflow so it cannot
  be poisoned by a cached real-brew call from another test.
- Add tests/test_exceptions_and_error_codes.py (423 lines / ~64 cases)
  covering StructuredError, ErrorCode enums, create_error, category/
  severity filters, and all nine VersionTrackerError subclasses with
  their optional context parameters.

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

* test: relax large dataset performance threshold and ignore coverage.json

Bump execution time limit 5s → 10s to prevent flaky CI on slow runners.
Add coverage.json to .gitignore (generated by coverage tools).

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

---------

Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: docdyhr

.gitignore

@@ -205,6 +205,7 @@ htmlcov/
 .cache
 nosetests.xml
 coverage.xml
+coverage.json
 *.cover
 *.py,cover
 .hypothesis/

tests/test_end_to_end_integration.py

@@ -28,6 +28,15 @@
 class TestEndToEndIntegration:
     """End-to-end integration tests for complete workflows."""
 
+    @pytest.fixture(autouse=True)
+    def clear_lru_caches(self):
+        """Clear lru_cache state between tests to prevent cross-test contamination."""
+        from versiontracker.apps.finder import clear_homebrew_casks_cache
+
+        clear_homebrew_casks_cache()
+        yield
+        clear_homebrew_casks_cache()
+
     @pytest.fixture
     def temp_config_dir(self):
         """Create temporary configuration directory."""
@@ -170,11 +179,17 @@ def test_configuration_management_workflow(self, temp_config_dir):
 
     def test_auto_updates_management_workflow(self, mock_homebrew_casks, mock_homebrew_available):
         """Test auto-updates management workflow."""
-        # Mock has_auto_updates to avoid real brew subprocess calls
+        # Patch get_homebrew_casks at the handler import site to avoid real brew calls
+        # and prevent lru_cache from returning stale data from other tests.
         with (
             mock.patch("builtins.input", return_value="y"),
             mock.patch("sys.argv", ["versiontracker", "--blacklist-auto-updates"]),
+            mock.patch(
+                "versiontracker.handlers.auto_update_handlers.get_homebrew_casks",
+                return_value=["firefox", "google-chrome"],
+            ),
             mock.patch("versiontracker.homebrew.has_auto_updates", return_value=True),
+            mock.patch("versiontracker.homebrew.get_casks_with_auto_updates", return_value=[]),
         ):
             result = versiontracker_main()