fix: users by email are now exposed through plugin interface

machine/plugins/base.py

@@ -64,6 +64,18 @@ def users(self) -> dict[str, User]:
         """
         return self._client.users
 
+    @property
+    def users_by_email(self) -> dict[str, User]:
+        """Dictionary of all users in the Slack workspace by email
+
+        **Note**: not every user might have an email address in their profile, so this
+        dictionary might not contain all users in the Slack workspace
+
+        :return: a dictionary of all users in the Slack workspace, where the key is the email and
+            the value is a [`User`][machine.models.user.User] object
+        """
+        return self._client.users
+
     @property
     def channels(self) -> dict[str, Channel]:
         """List of all channels in the Slack workspace
@@ -101,6 +113,22 @@ def find_channel_by_name(self, channel_name: str) -> Channel | None:
                 return c
         return None
 
+    def get_user_by_id(self, user_id: str) -> User | None:
+        """Get a user by their ID.
+
+        :param user_id: The ID of the user to retrieve.
+        :return: The user if found, None otherwise.
+        """
+        return self.users.get(user_id)
+
+    def get_user_by_email(self, email: str) -> User | None:
+        """Get a user by their email address.
+
+        :param email: The email address of the user to retrieve.
+        :return: The user if found, None otherwise.
+        """
+        return self._client.get_user_by_email(email)
+
     @property
     def bot_info(self) -> dict[str, Any]:
         """Information about the bot user in Slack