fix: add explicit tailnet gateway bind

src/config/legacy.migrations.part-3.ts

@@ -143,21 +143,4 @@ export const LEGACY_CONFIG_MIGRATIONS_PART_3: LegacyConfigMigration[] = [
       delete raw.identity;
     },
   },
-  {
-    id: "bind-tailnet->auto",
-    describe: "Remap gateway bind 'tailnet' to 'auto'",
-    apply: (raw, changes) => {
-      const migrateBind = (obj: Record<string, unknown> | null | undefined, key: string) => {
-        if (!obj) return;
-        const bind = obj.bind;
-        if (bind === "tailnet") {
-          obj.bind = "auto";
-          changes.push(`Migrated ${key}.bind from 'tailnet' to 'auto'.`);
-        }
-      };
-
-      const gateway = getRecord(raw.gateway);
-      migrateBind(gateway, "gateway");
-    },
-  },
 ];