chore(deps): Go 1.25.7 → 1.26.3

go.mod toolchain auf go 1.26.0; tests + cross-compile amd64/arm64 grün.
CLAUDE.md Stack-Tabelle nachgezogen. /usr/local/go.bak hält 1.25.7
falls Rollback nötig.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

go.mod

@@ -1,12 +1,13 @@
 module git.netcell-it.de/projekte/edgeguard-native
 
-go 1.25.7
+go 1.26.0
 
 require (
 	github.com/gin-gonic/gin v1.10.0
 	github.com/go-acme/lego/v4 v4.35.2
 	github.com/jackc/pgx/v5 v5.9.2
 	github.com/pressly/goose/v3 v3.27.1
+	github.com/skip2/go-qrcode v0.0.0-20200617195104-da1b6568686e
 	golang.org/x/crypto v0.51.0
 )
 
@@ -37,7 +38,6 @@ require (
 	github.com/modern-go/reflect2 v1.0.3-0.20250322232337-35a7c28c31ee // indirect
 	github.com/pelletier/go-toml/v2 v2.2.2 // indirect
 	github.com/sethvargo/go-retry v0.3.0 // indirect
-	github.com/skip2/go-qrcode v0.0.0-20200617195104-da1b6568686e // indirect
 	github.com/twitchyliquid64/golang-asm v0.15.1 // indirect
 	github.com/ugorji/go/codec v1.2.12 // indirect
 	go.uber.org/multierr v1.11.0 // indirect