chore: upgrade to Go 1.26.2 with toolchain directive

[sebrandon1]

Summary

Set go 1.26 as the minimum language version with toolchain go1.26.2 in go.mod for improved compatibility and security.

Security Fixes

Go 1.26.2 announcement — 10 CVEs fixed:

CVE	Package	Issue
CVE-2026-27140	cmd/go	Code smuggling via crafted SWIG file names
CVE-2026-27143	cmd/compile	Invalid arithmetic over loop induction variables
CVE-2026-27144	cmd/compile	Incorrect pointer unwrapping in memory moves
CVE-2026-32280	crypto/x509	DoS via unlimited chain building with many intermediates
CVE-2026-32281	crypto/x509	DoS via inefficient policy mapping validation
CVE-2026-32282	os (unix)	Symlink traversal in Root.Chmod on Linux
CVE-2026-32283	crypto/tls	TLS 1.3 deadlock from multiple key update messages
CVE-2026-32288	archive/tar	Unbounded memory allocation from sparse map entries
CVE-2026-32289	html/template	XSS via incorrect escaping in JS template literals
CVE-2026-33810	crypto/x509	DNS constraint bypass with case-sensitive wildcards

Related PRs

• chore: upgrade to Go 1.26.2 with toolchain directive certsuite#3555
• chore: upgrade to Go 1.26.2 with toolchain directive certsuite-claim#166
• chore: upgrade to Go 1.26.2 with toolchain directive certsuite-overview#133
• chore: upgrade to Go 1.26.2 with toolchain directive certsuite-qe#1433
• chore: upgrade to Go 1.26.2 with toolchain directive checks#31
• chore: upgrade to Go 1.26.2 with toolchain directive collector#675
• chore: upgrade to Go 1.26.2 with toolchain directive cr-scale-operator#10
• chore: upgrade to Go 1.26.2 with toolchain directive kpi-collection-tool#87
• chore: upgrade to Go 1.26.2 with toolchain directive oct#426
• chore: upgrade to Go 1.26.2 with toolchain directive perfdive#58
• chore: upgrade to Go 1.26.2 with toolchain directive privileged-daemonset#350