fix: bump Go to 1.26.1 to resolve 4 stdlib vulnerabilities

Fixes GO-2026-4599, GO-2026-4600 (crypto/x509),
GO-2026-4601 (net/url), GO-2026-4602 (os).
govulncheck now reports zero vulnerabilities.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: julianknutsen

go.mod

@@ -1,6 +1,6 @@
 module github.com/gastownhall/wasteland
 
-go 1.24.13
+go 1.26.1
 
 require (
 	github.com/charmbracelet/bubbles v1.0.0