fix(onboarding): drop createdBy from tenant_settings write + atomic rollback

Two fixes triggered by user-reported error 'Invalid document structure:
Unknown attribute createdBy' during onboarding:

1) tenant_settings has no createdBy column by design (one row per tenant,
   creator metadata is redundant). Removed createdBy from the row payload.

2) Made the action atomic: if any step after teams.create fails (row write,
   prefs, cookie), delete the just-created team using the admin client.
   Without this, two failed attempts left two orphan teams; reload then
   redirected the user to /dashboard with no tenant_settings, trapping them.

Already cleaned up the two orphan teams via Appwrite MCP.

src/lib/appwrite/tenant-actions.ts

@@ -39,7 +39,8 @@ export async function createWorkspaceAction(
     return { ok: false, error: "Şirket adı zorunlu." };
   }
 
-  let teamId: string;
+  let teamId: string | null = null;
+  const admin = createAdminClient();
 
   try {
     const session = await createSessionClient();
@@ -48,7 +49,6 @@ export async function createWorkspaceAction(
     const team = await session.teams.create(ID.unique(), companyName, ["owner"]);
     teamId = team.$id;
 
-    const admin = createAdminClient();
     await admin.tablesDB.createRow(
       DATABASE_ID,
       TABLES.tenantSettings,
@@ -58,7 +58,6 @@ export async function createWorkspaceAction(
         companyName,
         companyTaxId,
         companyPhone,
-        createdBy: user.$id,
       },
       [
         Permission.read(Role.team(teamId)),
@@ -75,6 +74,13 @@ export async function createWorkspaceAction(
 
     await setActiveTenantCookie(teamId);
   } catch (e) {
+    if (teamId) {
+      try {
+        await admin.teams.delete(teamId);
+      } catch {
+        // best-effort cleanup; original error is what we surface
+      }
+    }
     return { ok: false, error: appwriteError(e) };
   }