refactor(ui): Sidebar 1:1 an enconf-Pattern angleichen

- <aside> → <nav> als Root-Element
- Section-Label-Div NEBEN dem <ul> (vorher verschachtelt)
- <NavLink>-Callback → <Link> + location.pathname-Vergleich (Pattern
  identisch zu netcell-webpanel/management-ui/src/components/Layout/Sidebar.tsx)
- nmg-prefix CSS-Variable `--nmg-sidebar-text` entfernt, Textfarbe
  direkt #94A3B8 (enconf-Standard)

Färbung war schon enconf-konform (Gradient #0B1426→#101D33→#0D1829,
Akzent-Stab #1677ff mit color-mix tint), nur Struktur+Markup zogen
nach.

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

cmd/edgeguard-api/main.go

@@ -48,7 +48,7 @@ import (
 	wgsvc "git.netcell-it.de/projekte/edgeguard-native/internal/services/wireguard"
 )
 
-var version = "1.0.56"
+var version = "1.0.57"
 
 func main() {
 	addr := os.Getenv("EDGEGUARD_API_ADDR")

cmd/edgeguard-ctl/main.go

@@ -9,7 +9,7 @@ import (
 	"os"
 )
 
-var version = "1.0.56"
+var version = "1.0.57"
 
 const usage = `edgeguard-ctl — EdgeGuard CLI
 

cmd/edgeguard-scheduler/main.go

@@ -24,7 +24,7 @@ import (
 	"git.netcell-it.de/projekte/edgeguard-native/internal/services/tlscerts"
 )
 
-var version = "1.0.56"
+var version = "1.0.57"
 
 const (
 	// renewTickInterval — how often we re-evaluate expiring certs.