docs: add invite Client Docs (litmuschaos#7)

Signed-off-by: 잉퓨 <[email protected]>

Author: inpyu

docs/invitation.md

@@ -0,0 +1,103 @@
+
+# Invitation Request
+
+```mermaid
+classDiagram
+    class AcceptInvitationRequest {
+        -String projectId
+        -String userId
+        +AcceptInvitationRequest(String projectId, String userId)
+    }
+```
+```mermaid
+classDiagram
+    class DeclineInvitationRequest {
+        -String projectId
+        -String userId
+        +DeclineInvitationRequest(String projectId, String userId)
+    }
+```
+```mermaid
+classDiagram
+    class InviteUsersRequest {
+        -String projectId
+        -String userId
+        +InviteUsersRequest(String projectId, String userId)
+    }
+```
+```mermaid
+classDiagram
+    class ListInvitationRequest {
+        -String projectId
+        -String userId
+        +ListInvitationRequest(String projectId, String userId)
+    }
+```
+```mermaid
+classDiagram
+    class RemoveInvitationRequest {
+        -String projectId
+        -String userId
+        +RemoveInvitationRequest(String projectId, String userId)
+    }
+```
+```mermaid
+classDiagram
+    class SendInvitationRequest {
+        -String projectId
+        -String userId
+        -String role
+        +SendInvitationRequest(String projectId, String userId, String role)
+    }
+```
+
+# Invitation Response
+```mermaid
+classDiagram
+
+    class InviteUsersResponse {
+        -long updatedAt
+        -long createdAt
+        -UserInfo createdBy
+        -UserInfo updatedBy
+        -boolean isRemoved
+        -String userID
+        -String username
+        -String salt
+        -String email
+        -String name
+        -String role
+        -boolean isInitialLogin
+        +InviteUsersResponse(long updatedAt, long createdAt, UserInfo createdBy, UserInfo updatedBy, boolean isRemoved, String userID, String username, String salt, String email, String name, String role, boolean isInitialLogin)
+    }
+
+    class UserInfo {
+        -String userID
+        -String username
+        -String email
+        +UserInfo(String userID, String username, String email)
+    }
+    InviteUsersResponse --> UserInfo
+```
+```mermaid
+classDiagram
+    class ListInvitationResponse {
+        -String projectID
+        -String projectName
+        -ProjectUser projectOwner
+        -String invitationRole
+        +ListInvitationResponse(String projectID, String projectName, ProjectUser projectOwner, String invitationRole)
+    }
+
+    class ProjectUser {
+        -String userID
+        -String username
+        -String email
+        -String name
+        -String role
+        -String invitation
+        -long joinedAt
+        +ProjectUser(String userID, String username, String email, String name, String role, String invitation, long joinedAt)
+    }
+    ListInvitationResponse --> ProjectUser
+```