fix(toolchain): upgrade to go1.26.0 to resolve stdlib CVEs

govulncheck reported 18 stdlib vulnerabilities against go1.24.4
(net/url, crypto/tls, crypto/x509, archive/zip, archive/tar,
encoding/asn1, encoding/pem, net/textproto, net/http, net/mail,
os/exec, database/sql).  Upgrading toolchain go1.24.4 -> go1.26.0
clears all of them.

  go 1.24.0          (minimum requirement unchanged)
  toolchain go1.26.0 (build toolchain upgraded)

Author: aynaash

go.mod

@@ -2,7 +2,7 @@ module nextdeploy
 
 go 1.24.0
 
-toolchain go1.24.4
+toolchain go1.26.0
 
 require (
 	github.com/AlecAivazis/survey/v2 v2.3.7