fix(api): bump go toolchain for security audit

Raise the API module to go1.26.2 so setup-go stops selecting a vulnerable standard library release, and add a regression test that fails on affected 1.26.x toolchains.

Closes #14

apps/api/go.mod

@@ -1,6 +1,6 @@
 module github.com/xdrop/monorepo
 
-go 1.26.1
+go 1.26.2
 
 require (
 	github.com/aws/aws-sdk-go-v2 v1.41.5

apps/api/internal/testutil/toolchain_test.go

@@ -0,0 +1,57 @@
+package testutil
+
+import (
+	"regexp"
+	"runtime"
+	"strconv"
+	"testing"
+)
+
+var goReleaseVersionPattern = regexp.MustCompile(`^go(\d+)\.(\d+)(?:\.(\d+))?`)
+
+func TestRequiresPatchedGoToolchain(t *testing.T) {
+	t.Parallel()
+
+	major, minor, patch, ok := parseGoReleaseVersion(runtime.Version())
+	if !ok {
+		t.Skipf("skipping toolchain guard for non-release Go version %q", runtime.Version())
+	}
+
+	if major > 1 || (major == 1 && minor > 26) {
+		return
+	}
+
+	if major == 1 && minor == 26 && patch < 2 {
+		t.Fatalf(
+			"Go toolchain %q is below the minimum patched version go1.26.2 required by the security audit",
+			runtime.Version(),
+		)
+	}
+}
+
+func parseGoReleaseVersion(version string) (int, int, int, bool) {
+	matches := goReleaseVersionPattern.FindStringSubmatch(version)
+	if matches == nil {
+		return 0, 0, 0, false
+	}
+
+	major, err := strconv.Atoi(matches[1])
+	if err != nil {
+		return 0, 0, 0, false
+	}
+
+	minor, err := strconv.Atoi(matches[2])
+	if err != nil {
+		return 0, 0, 0, false
+	}
+
+	patch := 0
+	if matches[3] != "" {
+		patch, err = strconv.Atoi(matches[3])
+		if err != nil {
+			return 0, 0, 0, false
+		}
+	}
+
+	return major, minor, patch, true
+}