refactor: rename platform/ → sdk/ to avoid stdlib conflict

platform/ shadowed Python's stdlib platform module, breaking
aiogram/aiohttp/multidict at import time. Renamed to sdk/ and
updated all imports across core/, tests/, and adapter/telegram/.

tests/core/test_auth.py

@@ -2,7 +2,7 @@
 import pytest
 from core.auth import AuthManager
 from core.store import InMemoryStore
-from platform.mock import MockPlatformClient
+from sdk.mock import MockPlatformClient
 
 
 @pytest.fixture

tests/core/test_chat.py

@@ -2,7 +2,7 @@
 import pytest
 from core.chat import ChatManager
 from core.store import InMemoryStore
-from platform.mock import MockPlatformClient
+from sdk.mock import MockPlatformClient
 
 
 @pytest.fixture

tests/core/test_dispatcher.py

@@ -9,7 +9,7 @@ from core.chat import ChatManager
 from core.auth import AuthManager
 from core.settings import SettingsManager
 from core.store import InMemoryStore
-from platform.mock import MockPlatformClient
+from sdk.mock import MockPlatformClient
 
 
 @pytest.fixture

tests/core/test_integration.py

@@ -4,7 +4,7 @@ Smoke test: полный цикл через dispatcher + реальные manag
 Имитирует что делает адаптер (Telegram или Matrix) при получении события.
 """
 import pytest
-from platform.mock import MockPlatformClient
+from sdk.mock import MockPlatformClient
 from core.store import InMemoryStore
 from core.chat import ChatManager
 from core.auth import AuthManager

tests/core/test_settings.py

@@ -3,7 +3,7 @@ import pytest
 from core.settings import SettingsManager
 from core.store import InMemoryStore
 from core.protocol import SettingsAction
-from platform.mock import MockPlatformClient
+from sdk.mock import MockPlatformClient
 
 
 @pytest.fixture

tests/core/test_voice_slot.py

@@ -6,7 +6,7 @@ from core.store import InMemoryStore
 from core.auth import AuthManager
 from core.chat import ChatManager
 from core.settings import SettingsManager
-from platform.mock import MockPlatformClient
+from sdk.mock import MockPlatformClient
 
 
 @pytest.fixture

tests/platform/test_mock.py

@@ -1,6 +1,6 @@
 # tests/platform/test_mock.py
-from platform.mock import MockPlatformClient
-from platform.interface import User, MessageResponse, UserSettings
+from sdk.mock import MockPlatformClient
+from sdk.interface import User, MessageResponse, UserSettings
 from core.protocol import SettingsAction