docs-and-mcps (#1)

Reviewed-on: #1
Co-authored-by: Vishesh 'ironeagle' Bangotra <aetoskia@gmail.com>
Co-committed-by: Vishesh 'ironeagle' Bangotra <aetoskia@gmail.com>

mail_intake/credentials/store.pyi

@@ -0,0 +1,12 @@
+from abc import ABC, abstractmethod
+from typing import Generic, Optional, TypeVar
+
+T = TypeVar("T")
+
+class CredentialStore(ABC, Generic[T]):
+    @abstractmethod
+    def load(self) -> Optional[T]: ...
+    @abstractmethod
+    def save(self, credentials: T) -> None: ...
+    @abstractmethod
+    def clear(self) -> None: ...