refactor(core,logger)migrate to CherryPickObserver API and drop CherryPickLogger

BREAKING CHANGE:
- Removed the deprecated CherryPickLogger interface from cherrypick
- Logger/adapters (e.g., talker_cherrypick_logger) must now implement CherryPickObserver
- talker_cherrypick_logger: replace TalkerCherryPickLogger with TalkerCherryPickObserver
- All usages, docs, tests migrated to observer API
- Improved test mocks and integration tests for observer pattern
- Removed obsolete files: cherrypick/src/logger.dart, talker_cherrypick_logger/src/talker_cherrypick_logger.dart
- Updated README and example usages for new CherryPickObserver model

This refactor introduces a unified observer pattern (CherryPickObserver) to handle all DI lifecycle events, replacing the limited info/warn/error logger pattern.
All external logging adapters and integrations must migrate to use CherryPickObserver.

talker_cherrypick_logger/lib/src/talker_cherrypick_observer.dart

@@ -0,0 +1,66 @@
+import 'package:cherrypick/cherrypick.dart';
+import 'package:talker/talker.dart';
+
+/// CherryPickObserver-адаптер для логирования событий CherryPick через Talker
+class TalkerCherryPickObserver implements CherryPickObserver {
+  final Talker talker;
+
+  TalkerCherryPickObserver(this.talker);
+
+  @override
+  void onBindingRegistered(String name, Type type, {String? scopeName}) {
+    talker.info('[binding][CherryPick] $name — $type (scope: $scopeName)');
+  }
+  @override
+  void onInstanceRequested(String name, Type type, {String? scopeName}) {
+    talker.info('[request][CherryPick] $name — $type (scope: $scopeName)');
+  }
+  @override
+  void onInstanceCreated(String name, Type type, Object instance, {String? scopeName}) {
+    talker.info('[create][CherryPick] $name — $type => $instance (scope: $scopeName)');
+  }
+  @override
+  void onInstanceDisposed(String name, Type type, Object instance, {String? scopeName}) {
+    talker.info('[dispose][CherryPick] $name — $type => $instance (scope: $scopeName)');
+  }
+  @override
+  void onModulesInstalled(List<String> modules, {String? scopeName}) {
+    talker.info('[modules installed][CherryPick] ${modules.join(', ')} (scope: $scopeName)');
+  }
+  @override
+  void onModulesRemoved(List<String> modules, {String? scopeName}) {
+    talker.info('[modules removed][CherryPick] ${modules.join(', ')} (scope: $scopeName)');
+  }
+  @override
+  void onScopeOpened(String name) {
+    talker.info('[scope opened][CherryPick] $name');
+  }
+  @override
+  void onScopeClosed(String name) {
+    talker.info('[scope closed][CherryPick] $name');
+  }
+  @override
+  void onCycleDetected(List<String> chain, {String? scopeName}) {
+    talker.warning('[cycle][CherryPick] Detected: ${chain.join(' -> ')}${scopeName != null ? ' (scope: $scopeName)' : ''}');
+  }
+  @override
+  void onCacheHit(String name, Type type, {String? scopeName}) {
+    talker.info('[cache hit][CherryPick] $name — $type (scope: $scopeName)');
+  }
+  @override
+  void onCacheMiss(String name, Type type, {String? scopeName}) {
+    talker.info('[cache miss][CherryPick] $name — $type (scope: $scopeName)');
+  }
+  @override
+  void onDiagnostic(String message, {Object? details}) {
+    talker.verbose('[diagnostic][CherryPick] $message ${details ?? ''}');
+  }
+  @override
+  void onWarning(String message, {Object? details}) {
+    talker.warning('[warn][CherryPick] $message ${details ?? ''}');
+  }
+  @override
+  void onError(String message, Object? error, StackTrace? stackTrace) {
+    talker.handle(error ?? '[CherryPick] $message', stackTrace, '[error][CherryPick] $message');
+  }
+}