test(core): extend coverage — console, errors, log, service, time, benchmark

Add missing test modules for previously untested core areas:
- console: ForegroundColorEnum, BackgroundColorEnum, Console methods
- errors: dependency_error, module_dependency_error
- log: LogLevel ordering/values, LogSettings, Logger (should_log, format, file write, fatal)
- service: HostedService, StartupTask, CronjobABC (start/stop/loop/task cancellation)
- time: TimeFormatSettings properties and setters
- utils: Benchmark.time / .memory / .all call-count and output

Also fix existing test files: environment cleanup, cron exception specificity,
json_processor kwargs bug doc, configuration_model_abc to_dict bug doc.
All 199 tests pass, black clean.

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

test/core/environment/environment_test.py

@@ -4,6 +4,18 @@ from cpl.core.environment.environment import Environment
 from cpl.core.environment.environment_enum import EnvironmentEnum
 
 
+@pytest.fixture(autouse=True)
+def restore_env():
+    """Restore touched env vars after each test to prevent pollution."""
+    original = dict(os.environ)
+    yield
+    for key in list(os.environ.keys()):
+        if key not in original:
+            del os.environ[key]
+        elif os.environ[key] != original[key]:
+            os.environ[key] = original[key]
+
+
 def test_set_and_get_environment_valid():
     for env in EnvironmentEnum:
         Environment.set_environment(env.value)