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/time/cron_test.py

@@ -56,5 +56,5 @@ def test_custom_start_time():
 
 
 def test_invalid_cron_expression():
-    with pytest.raises(Exception):
+    with pytest.raises((ValueError, KeyError)):
         Cron("invalid expression")