github 0auth fixes

packages/backend/convex/auth.ts

@@ -17,8 +17,13 @@ export const authComponent = createClient<DataModel>(components.betterAuth);
 
 const createAuth = (ctx: GenericCtx<DataModel>) =>
   betterAuth({
+    account: {
+      accountLinking: {
+        allowDifferentEmails: true,
+      },
+    },
     advanced: { useSecureCookies: siteUrl.startsWith("https://") },
-    baseURL: env.CONVEX_SITE_URL,
+    baseURL: siteUrl,
     database: authComponent.adapter(ctx),
     emailAndPassword: {
       enabled: true,

packages/backend/convex/gitConnections.ts

@@ -80,13 +80,13 @@ const fetchGiteaUser = async (
     );
   }
   const user = (await response.json()) as {
-    readonly email?: string;
+    readonly email?: string | null;
     readonly id: number;
     readonly login: string;
   };
   return {
     externalAccountId: String(user.id),
-    externalEmail: user.email,
+    externalEmail: user.email ?? undefined,
     externalUsername: user.login,
   };
 };
@@ -105,13 +105,13 @@ const fetchGithubUser = async (token: string): Promise<ExternalUserInfo> => {
     );
   }
   const user = (await response.json()) as {
-    readonly email?: string;
+    readonly email?: string | null;
     readonly id: number;
     readonly login: string;
   };
   return {
     externalAccountId: String(user.id),
-    externalEmail: user.email,
+    externalEmail: user.email ?? undefined,
     externalUsername: user.login,
   };
 };