feat: Implement identity management and safety checks

src/types/identity.ts

@@ -0,0 +1,33 @@
+/**
+ * Type definitions for user identity and OAuth provider management
+ */
+
+export interface UserIdentity {
+  id: string;
+  user_id: string;
+  identity_data: {
+    email?: string;
+    full_name?: string;
+    avatar_url?: string;
+    [key: string]: any;
+  };
+  provider: 'google' | 'discord' | 'email' | 'github' | string;
+  created_at: string;
+  updated_at: string;
+  last_sign_in_at: string;
+}
+
+export type OAuthProvider = 'google' | 'discord';
+
+export interface IdentitySafetyCheck {
+  canDisconnect: boolean;
+  reason?: 'last_identity' | 'no_password_backup' | 'safe';
+  hasPasswordAuth: boolean;
+  totalIdentities: number;
+  oauthIdentities: number;
+}
+
+export interface IdentityOperationResult {
+  success: boolean;
+  error?: string;
+}